A Review of Transport Policies in Support of Climate Actions in Asian Cities and Countries

: Asia is one of the continents that is the most affected by the impacts of climate change. Asian countries need to take climate actions and mitigate emissions from the urban passenger transport sector. Despite some progress in improving urban mobility in Asian cities, greenhouse gas emissions from the transport sector continue to rise. Policy makers who are responsible for managing mobilities must play a major role in decarbonizing the transport sector. In this context, this paper reviews the efforts of selected Asian countries and cities towards reducing greenhouse gas emissions from the urban transport sector. It will analyze their pledges in the Nationally Determined Contributions submitted to the United Nations Framework Convention on Climate Change and will review their relevant transport sector strategies, policies, and practices. It will also look at trends in transport sector emissions and air pollution in different cities, including the short-term impacts of COVID-19. Lastly, it reviews governance issues and the roles that institutions should play to implement polices to decarbonize transport. Based on this analysis, this paper offers policy suggestions to accelerate actions, enhance cross-sectoral coordination, and move towards carbon neutrality in the transport sector in Asia.


Introduction
We are overwhelmed with news about extreme weather events and their impacts on our lives almost every day. Extreme heat waves in North America [1], floods in Nepal, China, and India [2,3], wildfires in the United States, Australia, and Southern Europe, and haze in Siberia [4] are just some of the many examples of these types of extreme weather events. Amid these disasters, the Intergovernmental Panel on Climate Change, or the IPPC, has recently released the first part of the Sixth Assessment Report, Climate Change 2021: The Physical Science Basis [5][6][7].
Although all continents are affected by climate change, Asia is one of the most affected. Bangladesh, China, Japan, Indonesia, and the Philippines are frequented by severe climate events such as floods, cyclones, and tsunamis. Sometimes, climate events combine with other natural and human-made disasters such as earthquakes. The Philippines, for example, is extremely vulnerable to climate-related and geological hazards, with tropical cyclones causing havoc for life and infrastructure every year. Losses and damages from extreme weather events in the Philippines were estimated to have reached 4% of the GDP in 2013 due to Super Typhoon Haiyan [8].
Today, it is widely accepted that human-induced activities are responsible for the increase in the frequency and intensity of climate events and global warming [9]. The IPCC reports suggest that it is possible to mitigate the anticipated rise in global temperature by reducing greenhouse gas emissions. It also singles out cities as hotspots for global warming due to their lack of vegetation and the heat retaining properties of urban infrastructure [9].
Cities are hubs and drivers of economic activity; they provide employment and economic growth. Meanwhile, urban transport systems are the wheels of this growth. The urban transport system makes goods accessible and allows people to commute to jobs and Earth 2021, 2 732 schools. Asian cities are developing urban transport systems and infrastructure to cater to the needs of growing urban populations. The economic boom in Asia has increased personal income, which, in turn, enables citizens to buy private cars or motorcycles. Owing to the pattern of urbanization and motorization occurring in Asia, the demand for passenger transport is expected to double between 2015 and 2050 [10]. Urban transport systems also generate negative externalities-Congestion, air pollution, noise pollution, and road accidents. Cities are responsible for three quarters of global energy consumption and greenhouse gas emissions [11].
The sustainability and livability of a city is affected by how mobility is managed in that city [12]. Cities are increasingly seen as potential areas for climate action [13]. There are opportunities for countries and cities to move at a faster pace towards a carbon neutral development path. Electric mobility, shifts to renewable energy sources, and the improvement of public transport are some of the key transport strategies listed in the Nationally Determined Contributions (NDCs) of Asian countries [14]. However, only a few Asian countries such as Singapore, Japan and Uzbekistan have managed to reduce emissions [15]. In addition, the COVID-19 pandemic has had a profound impact on people's mobility and urban public transport systems. The pandemic has forced people to change their travel behaviours; many people have opted for active mobility, alternative work modalities, virtual meetings, and online shopping, leading to some short-term reductions in travel demand.
Against this backdrop, the current paper reviews the efforts of Asian cities and countries in mitigating greenhouse gas emissions in the urban transport sector. It will analyze transport-related commitments made by selected countries in the NDCs submitted to the United Nations Framework Convention on Climate Change (UNFCCC) and will review their transport sector strategies and polices. It will also look at transport sector emission and air pollution trends in cities, including the short-term impacts of COVID-19. As urbanization and the demand for mobility are expected to grow, proper planning and management can help to reduce transport emissions and to support climate actions in cities. Based on this review and analysis, the current paper offers policy suggestions towards carbon neutrality in the urban transport sector in Asian cities.

Review of Urban Mobility and Environment in Asian Cities
Cities are production hubs and economic centres and account for about 80% Asia's economic output. More than 50% of the Asian population are living in urban areas, and cities are a source of more than 70% of greenhouse gas (GHG) emissions and pollution [16]. By 2030, 2.7 billion people will be living in urban areas in Asia [17]. The number of vehicles is also increasing in Asian cities. This rapid urbanization and the growth and concentration of motor vehicles in urban areas are putting pressure on already congested urban public transport systems.
Asian countries and cities are working to improve their public transport systems. Public buses, bus rapid transit (BRT) systems, and metros are popular forms of public transit. As of 2020, BRT systems are operating in 44 cities in Asia, with 9.5 million passengers transported per day along 1625 km of routes [18]. In Jakarta, Dhaka, Bangkok, Hanoi, and Ho Chi Minh City, mass transit systems are being expanded as well as in many cities in China, India, and Iran. However, the mode share of public transport is still low in many cities, and personal vehicles are still the dominant transport mode in many cities.
The rise in transport demand and the use of personal vehicles has led to traffic congestion, which has caused negative externalities such as economic losses, increases in energy consumption and GHG emissions, and worsening air pollution. Among the top 10 highly congested cities in the world, eight are from Asia. Mumbai, Manila, Istanbul, Bengaluru, New Delhi, and Bangkok are Asian cities with high levels of traffic congestion [19].
The concentration of population, economic activities, and infrastructure development have made cities flashpoints for climate change. Asian cities in particular face unique challenges-Enhancing mobility, ensuring accessibility, and providing high quality and efficient mobility services, while at the same time, minimizing congestion and pollution. On top of this, the increasing frequency and intensity of climate events severely affects the development and operation of mobility systems and there is an urgency to find solutions to these challenges. Passenger transport systems, which are responsible for 15% of GHG, have high potential to reduce emissions [20].
In recent years, frequent climate events have caused significant disruptions to transport operations [21]. There is climate event variability within Asia. Many Asian coastal cities will be affected by faster sea level increases. Extreme heat has increased, and cold has decreased in Asia. In East Asia, the frequency and intensity of precipitation will increase, and draught is expected to be more frequent. Meanwhile, rainfall will increase in the northern parts of Southeast Asia, monsoon precipitation will increase in South Asia, and droughts are expected to be severe in Southwest Asia [9].
There are huge opportunities for cities to respond to climate challenges and to reduce GHG emissions, such as by integrating land use and transport planning and promoting car free zones as well as promoting active mobility [22]. Some reports and studies argue that the electrification of the transport sector holds potential opportunity for climate change [22][23][24][25] but note that transitions to electric mobility need to be coupled with the replacement of fossil fuel vehicles [26]. Others advocate the need for comprehensive urban transport planning and changes in user behavior [27][28][29].
One of the challenges for countries is to translate these NDCs commitments into actions. In the case of South East Asian countries, for example, some studies ask whether current policies and plans are adequate to meet mitigation targets [30]. Others question the targeted pledges in the NDCs of South Asian countries and argue that their targets are not backed by adequate analysis [31]. Carbon emissions from transport in cities can be substantially reduced through targeted land use planning, improved public transport systems, and economic measures to encourage a mode shift to more energy efficient modes in South East Asian countries [32]. Some authors have argued that a systems approach in cities is necessary to deliver on climate change [33]. To deliver their climate pledges, practical approaches to sustainable urban mobility include setting long term visions, augmenting local capacities to implement projects, establishing clear funding mechanisms, and improving project development and selection [34].
There are plenty of examples from the Asian region and beyond of how urban mobility can be managed in response to the current climate crisis. Public transport management, the promotion of active mobility, and the introduction of stringent emission standards and fuel quality have been suggested to improve mobility and air quality in Kathmandu [35,36]. Yangon needs to focus on an integrated approach to enhance accessibility rather than simply addressing urban traffic congestion [37]. A study on Indian cities suggests that governance, strategic understanding, and interaction among all state and non-state actors is essential to integrate local development and climate actions [38]. Many Indian cities need transport policies and plans designed to move people rather than vehicles to reduce emissions and pollution and to manage the transport sector wisely [39]. A study on Tehran has analyzed an unlikely proposition for a total removal of cars and motorcycle in order to reduce pollution [40]. Another study looked at the potential of smart mobility to create a cleaner environment and to reduce emissions in European cities [41]. Assessment of the effectiveness of sustainable urban mobility plans in European cities suggest that many low-cost measures can be implemented at the local level [42]. Some researchers argue for non-technical solutions such as demand reduction measures as an effective way to cut emissions [43].
Much of the policy attention has been focused on mitigation measures in the transport sector. Given the increase in frequency and intensity of climate events in Asia, there is an urgent need for the transport sector to adapt to the impacts of climate change [44]. In addition to direct adaptation pathways such as enhancing the robustness of infrastructure, indirect pathways such as preparedness and changing the behaviours of vulnerable communities can be useful in enhancing the resilience of transport systems [45].
Asia is leading in efforts to improve urban mobility in cities. New mass transit systems have opened in Lahore, Jakarta, and Nagpur in India, while the expansion of urban transit network is progressing in many cities in China and Bangkok [15]. China has been implementing an electric vehicles promotion scheme to promote the transition towards electric mobility. The number of electric buses has reached more than half a million in China, and the three Chinese cities of Guangzhou, Shenzhen, and Xi'an operate public transport systems that are 100 percent electric.
During the COVID-19 pandemic, many governments ordered or encouraged their populace to stay at home. Though estimates vary, it is estimated that there was a 59% reduction in public transport trips due to COVID-19. Many countries have prioritized active mobility, as these mobilities have the potential to reduce emissions [46]. Such efforts were boosted during the pandemic, as city officials became concerned about the risk of transmission via public transport modes.
The next decade will be critical for Asia's transport sector to reduce GHG emissions and to contribute to the reversal of rising temperatures. Streamlined and innovative climate change governance, the analysis of "quick win" mitigation policies and choices of technology and costs [47][48][49], and simple carbon accounting methods to monitor progress can help make evidence-based decisions.
Countries have made various commitments at the global fora and in their NDCs, which now need to be translated into actions. Some of the pledges made by developing countries in their NDCs are conditional upon receiving international support. On the other hand, the involvement of transport organizations in developing NDCs and institutional arrangements that facilitates cooperation across sectors/ministries at the national and subnational levels can support the effective implementation of policies and pledges [50,51].

Methods and Data Sources
The current paper includes both quantitative and qualitative analyses of transport emission trends, NDCs commitments, policies, and practices for reducing emissions from transport, particularly urban transport systems. The quantitative assessment includes: (i) an analysis of passenger transport activities; (ii) an assessment of CO 2 emissions and motorization trends; (iii) a mode share of public, active, and informal transport; and (iv) air quality (PM2.5). The paper also looks at the short-term impacts of COVID-19 on air quality in some cities. The qualitative analysis reviews (i) GHG reduction targets in NDCs and transport strategies, policies, and practices and (ii) the governance, institutions, and financing of transport policies. The paper utilizes information and data from UNFCCC for transport sector commitments in NDCs [14], World Air Quality Reports [52,53], country and city mobility assessment reports [54], and data and feedback from urban transport stakeholders in Asian countries and cities.
Given the large number of cities in Asia, this study focuses on the transport policies and practices of selected cities, namely Dhaka, Surat, and Kathmandu from South Asia and Bangkok, Hanoi, and Greater Jakarta from South East Asia. These cities have different sizes, represent different spatial and economic characteristics, and have different public transport systems and services. Table 1 shows the basic characteristics and key public transport indicators of these cities. Based on the analysis, policy suggestions are offered towards reducing GHG emissions from transport that will contribute towards decarbonization and that will improve air quality in Asian cities. Source: [54].

Results
The first observation that can be made is that despite the many efforts of Asian countries to address climate change and to improve mobility, transport emissions are increasing across most countries in Asia. Some of the top carbon emitting countries in the world are located in Asia, and considerable efforts will be necessary to reduce emissions from the transport sector. The following sections present a broad analysis with respect to the assessment of transport section emissions, NDCs, transport policies and practices, vehicle fleet, air quality, improvement of public transport, share of active mobility, and governance, institutions, and financing issues for selected countries. Table 2 shows passenger transport activities, transport CO 2 emissions, and trends for the year 2019 for key countries. The number of passenger-km travelled is very high in India, the U.S.A., and China. The U.S.A., China, and India are top CO 2 emitters. India has registered the highest passenger activity growth rate of 122% during 2010-2019, while Japan has the lowest growth rate at 11%. In terms of per capita emissions, the U.S.A. is the highest emitter, with 5.4 tonnes per capita, followed by Iran, the U.K., and the Russian Federation, with 1.7 tonnes per capita [15]. Many Asian countries have set long term targets to decarbonize transport [26,[55][56][57] and to keep global warming below 2 • C. However, transport CO 2 emissions grew by 41% in Asia during 2010-2019, with China and India registering the highest growth rates. Only Japan and the U.K. have managed to reduce transport emissions. Other countries who have managed to reduce transport emissions are Mexico, Italy, Argentina, and France [15].

Assessment of Transport Sector Emissions
The IPCC has analyzed six scenarios that cover several ranges of future emissions, namely very high (SSP5-8.5), high (SSP3-7.0), intermediate (SSP2-4.5), low (SSP1-2.6), and very low (1-1.9) GHG emissions. Only the very low and low GHG emissions scenarios are likely to deliver below 2 • C global warming [9]. Figure 1 shows the average annual per capita CO 2 emissions from transport in selected cities. Tehran, Jaipur, Jakarta, and Ulaanbaatar have high emission values per capita. The low values shown for many cities could be due to population concentration and low levels of motorization.
There are multiple mitigation options for reducing emissions from the transport sector, and several modeling approaches have been used to analyze transport decarbonization pathway scenarios [26,[55][56][57][58]. Many suggest low-carbon pathways using the avoid-shiftimprove (ASI) framework [59][60][61]. Public transport needs to be oriented towards greener and more sustainable modes [62]. Within the ASI approach, the shift and improve strategies are considered to be more effective. Shifting to mass transit from private cars and using electric mobility can contribute to decarbonization efforts. In addition, the periodic monitoring of emission trends is important to track achievements. Accurate transport activity data and simple carbon accounting methodologies, including both top-down and bottom-up approaches, can be employed. Such transport decarbonization efforts need to start delivering results by 2030 and 2040. There are multiple mitigation options for reducing emissions from the transport sector, and several modeling approaches have been used to analyze transport decarbonization pathway scenarios [26,[55][56][57][58]. Many suggest low-carbon pathways using the avoidshift-improve (ASI) framework [59][60][61]. Public transport needs to be oriented towards greener and more sustainable modes [62]. Within the ASI approach, the shift and improve strategies are considered to be more effective. Shifting to mass transit from private cars and using electric mobility can contribute to decarbonization efforts. In addition, the periodic monitoring of emission trends is important to track achievements. Accurate transport activity data and simple carbon accounting methodologies, including both topdown and bottom-up approaches, can be employed. Such transport decarbonization efforts need to start delivering results by 2030 and 2040. Figure 2 shows the transport emissions mitigation measures in the NDCs of countries in the Asia-Pacific region. Primarily aimed at passenger transport, the top three emission mitigation strategies are the promotion of public bus transport, alternative energy sources such as biofuels, and electric mobility [14].  Figure 2 shows the transport emissions mitigation measures in the NDCs of countries in the Asia-Pacific region. Primarily aimed at passenger transport, the top three emission mitigation strategies are the promotion of public bus transport, alternative energy sources such as biofuels, and electric mobility [14].   Table 3 shows the mitigation targets in the NDCs of selected Asian countries and the details of mitigation the strategies for the transport sector. It shows that the GHG reduction targets of Thailand, Indonesia, the Philippines, and Vietnam are conditional upon receiving international support. Table 3. Mitigation targets and transport mitigation strategies in selected NDCs.

Countries
Mitigation Target in NDC by 2030 Polices and Strategies Related to Transport Bangladesh 15% GHG reduction "Avoid-Shift-Improve" framework, development of mass rapid transit (MRT) and bus rapid transit (BRT), energy efficient rail locomotives 20% GHG reduction (unconditional) Environmentally sustainable transport system (2013-2030), mode  Table 3 shows the mitigation targets in the NDCs of selected Asian countries and the details of mitigation the strategies for the transport sector. It shows that the GHG reduction targets of Thailand, Indonesia, the Philippines, and Vietnam are conditional upon receiving international support. Some of the common transport strategies (Figure 2 and Table 3) in the NDCs are: the improvement of public transport (bus, mass transit, and bus rapid transit); the use of renewable energy; the deployment of electric mobility; fuel economy and vehicle emissions standards; mode shift from road to rail; freight mode shift; the application of smart transport technologies; integrated land use and transport planning; and the promotion of non-motorized transport.

Growing Vehicle Fleets
Asia has also witnessed rapid motorization beyond what many cities are able to comfortably absorb. The difference in automobile ownership is still very significant across Asia. The motorization rate in developed Asian countries ranged from 417 to 819 vehicles per 1000 inhabitants compared to rates for developing countries, which ranged between 22 and 38 vehicles per 1000 inhabitants in 2015 [63]. Figure 3 shows the number of registered vehicles per 1000 inhabitants in East Asian countries from 2005 to 2019 [64]. As noted above, one focus of the shift strategy is to reduce the use of personal vehicles and to encourage people to use mass public transit, but high rates of vehicle ownership can be observed in Brunei, Malaysia, and Thailand. It is worth noting that only Singapore has managed to reduce this indicator.
Countries in South and South East Asia also have a high share of powered two and three wheelers, which adds to the congestion and air pollution problem in cities as well as road accidents. For example, the share of powered two and three wheelers in the total vehicle fleet is 93% in Vietnam, 83% in Indonesia, 71% in Sri Lanka, 73% in India, and 66% in Nepal [65]. Some countries, such as Bangladesh, China, Pakistan, and Nepal, are aiming to electrify their two-and three-wheeler fleets to reduce emissions.
per 1000 inhabitants compared to rates for developing countries, which ranged between 22 and 38 vehicles per 1000 inhabitants in 2015 [63]. Figure 3 shows the number of registered vehicles per 1000 inhabitants in East Asian countries from 2005 to 2019 [64]. As noted above, one focus of the shift strategy is to reduce the use of personal vehicles and to encourage people to use mass public transit, but high rates of vehicle ownership can be observed in Brunei, Malaysia, and Thailand. It is worth noting that only Singapore has managed to reduce this indicator. Countries in South and South East Asia also have a high share of powered two and three wheelers, which adds to the congestion and air pollution problem in cities as well as road accidents. For example, the share of powered two and three wheelers in the total vehicle fleet is 93% in Vietnam, 83% in Indonesia, 71% in Sri Lanka, 73% in India, and 66% in Nepal [65]. Some countries, such as Bangladesh, China, Pakistan, and Nepal, are aiming to electrify their two-and three-wheeler fleets to reduce emissions.

Air Quality
Particulate matter (PM) is a mixture of solid particles and liquid droplets found in the air. In Asia, about 92% of the population (4 billion people) is exposed to levels of air pollution that pose a significant risk to their health. The top 15 capital cities in the world with the highest level of PM2.5 concentrations in 2019 and 2020 are in Asia [52,53]. New Delhi, Kathmandu, Dhaka, Jakarta, Hanoi, and Colombo were all in the top 30 most polluted cities in the world in 2019, while Bangkok ranked 33rd.

Air Quality
Particulate matter (PM) is a mixture of solid particles and liquid droplets found in the air. In Asia, about 92% of the population (4 billion people) is exposed to levels of air pollution that pose a significant risk to their health. The top 15 capital cities in the world with the highest level of PM2.5 concentrations in 2019 and 2020 are in Asia [52,53]. New Delhi, Kathmandu, Dhaka, Jakarta, Hanoi, and Colombo were all in the top 30 most polluted cities in the world in 2019, while Bangkok ranked 33rd.
Transport emissions are a major contributor to air pollution. Due to the COVID-19 pandemic lockdowns and restrictions, air pollution levels decreased in 2020 in most countries. Table 4 shows the annual average air quality in 2019 and 2020. In all cities, there is an improvement in the air quality due to the restrictions placed on mobility. However, the air quality in all cities still exceeds the WHO target of 10 µg/m 3 for PM2.5. Among these cities, Metro Manila is the best in terms of air quality, while New Delhi is the most polluted city. One of the main reasons was for the improvements in air quality was the restrictions placed on private and public transportation, which reduced traffic on the roads. This indicates that when people reduce the use of their own vehicles or do not commute as much, air quality improves. However, lockdowns are not feasible as permanent solutions for improving air quality in Asian cities since they adversely impact economic activity. People need to travel for work and run their businesses, and countries cannot function with industries being shut down and people staying at home. Therefore, it is essential to look at long-term, sustainable solutions to control the traffic on roads and to reduce air pollution [66,67]. Even though these measures were temporary, they showed that if strategic policy measures to limit emissions are implemented, a low-carbon path can be realized.

Public Transport and Active Mobility
Asian cities have led the way for mass transit system development over the past two decades. Greater Jakarta has developed a subway and light rail transit system and also operates the largest BRT system in the world. Bangkok is expanding its urban rail network and is promoting biofuels and electric mobility. The construction of a subway system and BRT is progressing in Dhaka. In addition to public buses, Hanoi has a BRT system and is developing more mass transit systems. Surat is operating a BRT network. Kathmandu operates a bus system but has yet to develop a mass transit system. Among these only Jakarta has recently initiated an integrated fare system, all other cities have not implemented an integrated fare system for different public transport modes or service integration that would facilitate smooth transfers between systems.
Non-motorized transport or active mobility (cycling and walking) is another viable option in cities and settlements. A shift to active mobility would contribute to decarbonization efforts given that it is the cleanest form of mobility. Figure 4 shows the mode share of active mobility in commuting trips in selected Asian cities. It indicates that the share is higher than 20 per cent in many cities. The notably high shares in Bhopal, Kathmandu, and Yangon highlight the importance of active mobility in meeting the needs of urban residents. In the current context of COVID-19, there have been calls to place more emphasis on active mobility to facilitate social distancing. Increased investment for infrastructure and facilities for pedestrians and cyclists can provide low-cost mobility solutions in cities as well as help to reduce emissions [68].  The case of Kathmandu during COVID-19 further illustrates the importance of active mobility. Kathmandu employed various travel restriction measures to ensure the health and wellbeing of commuters and operators. Many commuters took to active mobility, using personal vehicles and motorcycles to maintain social distancing. In medium to longterm planning, there are calls to prioritize active mobility [69]. Recent policy statements from the federal government to promote electric public mobility and to relocate some industries out of the Kathmandu valley are encouraging [70]. These will help to improve congestion and accessibility to public transport as well as improve air pollution.
Various forms of informal transport or paratransit are prevalent in Asian cities, serving inner city areas and carrying a substantial share of urban passengers. In many cases, paratransit modes complement public transport systems. Jeepneys in Manila, angkots in Indonesia, songthaew and motorcycle taxis in Thailand, tempos in Nepal, and auto-rickshaws and cycle-rickshaws in India, Pakistan, and Bangladesh are some of the informal modes of transportation in Asia [71].
These forms of transport provide first and last mile connectivity in the overall urban The case of Kathmandu during COVID-19 further illustrates the importance of active mobility. Kathmandu employed various travel restriction measures to ensure the health and wellbeing of commuters and operators. Many commuters took to active mobility, using personal vehicles and motorcycles to maintain social distancing. In medium to long-term planning, there are calls to prioritize active mobility [69]. Recent policy statements from the federal government to promote electric public mobility and to relocate some industries out of the Kathmandu valley are encouraging [70]. These will help to improve congestion and accessibility to public transport as well as improve air pollution.
Various forms of informal transport or paratransit are prevalent in Asian cities, serving inner city areas and carrying a substantial share of urban passengers. In many cases, paratransit modes complement public transport systems. Jeepneys in Manila, angkots in Indonesia, songthaew and motorcycle taxis in Thailand, tempos in Nepal, and auto-Earth 2021, 2 740 rickshaws and cycle-rickshaws in India, Pakistan, and Bangladesh are some of the informal modes of transportation in Asia [71].
These forms of transport provide first and last mile connectivity in the overall urban transport chain. Figure 5 shows the mode share of informal transport in selected cities in Asia. It shows that for many cities, the share is higher than 20%, with the highest share of 58% in Khulna, followed by Dhaka with 54%. In recent years, paratransit service providers have started to use innovations and technologies to improve their services, such as GPS systems for booking and tracking. During the COVID-19 pandemic, a rise in the use of cashless payments using electronic payment platforms, QR codes, credit cards, and mobile banking could be seen. Given that informal transport is carrying a considerable share of urban commuters, these operators could also be targeted to reduce emissions. Support from authorities will be necessary to improve their service as well to shift towards renewable energy. For example, work is progressing to transform Jeepneys into electric Jeepneys in the Philippines, while most tempos are already electric in Kathmandu. Increases in the number of electric two and three wheelers can also be seen in Bangladesh and China.

Governance, Institutions and Financing
Decarbonization of transport requires an integrated approach to plan and implement policies. Collaboration among various levels of government and transport stakeholders as well as other sectors such as the energy, public works, and manufacturing sectors, is a prerequisite to translate the commitments made in the NDCs. The lack of thematic and institutional coordination is often cited as a major challenge to implement transport strategies [72]. In some cities, there are too many transport organizations with overlapping authority. To resolve this, some cities have established a coordination authority, such as the Dhaka Transport Coordination Authority in Dhaka and the Greater Jakarta Transport Authority in Jakarta. There is a plan to establish a new integrated valley transport authority in Kathmandu [73]. These authorities are expected to enhance coordination and to improve the planning, implementation, and management of public transport projects.
Nepal provides an example of the application of technologies for electric public buses. The federal government, the Bagmati provincial government, and the two metropolitan cities of Kathmandu and Lalitpur are jointly funding 300 electric buses to be operated by Sajha Yatayat, with the charging infrastructure to be installed by the Nepal Electricity Authority. A recent budget speech outlined the government's plan to operate electric buses in the Kathmandu Valley and to develop 500 charging stations, including through public-private partnerships [69]. With an abundance of green energy from hydropower, Nepal has huge potential to accelerate its transition to electric mobility. There

Governance, Institutions and Financing
Decarbonization of transport requires an integrated approach to plan and implement policies. Collaboration among various levels of government and transport stakeholders as well as other sectors such as the energy, public works, and manufacturing sectors, is a prerequisite to translate the commitments made in the NDCs. The lack of thematic and institutional coordination is often cited as a major challenge to implement transport strategies [72]. In some cities, there are too many transport organizations with overlapping authority. To resolve this, some cities have established a coordination authority, such as the Dhaka Transport Coordination Authority in Dhaka and the Greater Jakarta Transport Authority in Jakarta. There is a plan to establish a new integrated valley transport authority in Kathmandu [73]. These authorities are expected to enhance coordination and to improve the planning, implementation, and management of public transport projects.
Nepal provides an example of the application of technologies for electric public buses. The federal government, the Bagmati provincial government, and the two metropolitan cities of Kathmandu and Lalitpur are jointly funding 300 electric buses to be operated by Sajha Yatayat, with the charging infrastructure to be installed by the Nepal Electricity Authority. A recent budget speech outlined the government's plan to operate electric buses in the Kathmandu Valley and to develop 500 charging stations, including through public-private partnerships [69]. With an abundance of green energy from hydropower, Nepal has huge potential to accelerate its transition to electric mobility. There is already a call to the government from private sector entrepreneurs to initiate innovative strategic programmes for electric mobility [74]. The United Nations ESCAP has initiated a project to accelerate the transition to electric mobility in public transport and is piloting in countries that have a high share of renewable energy. The private sector has an important role to play, especially because the transition to electric mobility requires high initial investment.
As noted earlier, some NDC targets are linked to receiving additional international support. Governments need to commit resources for the implementation of transport strategies to deliver on NDCs, but international support is also needed to augment national efforts. Sometimes, there are also issues related to the absorptive capacity of countries [75].

Discussion
The IPCC's 6th Assessment Report is having a ripple effect. Many global leaders have vowed to act on its findings to limit GHG emissions and to control global warming. The transport sector, particularly in cities, has the potential to contribute to emission reductions. Many countries have announced their intention to make transport carbon neutral by 2050 [76,77]. The U.S.A. is planning to have new fuel efficiency standards and to increase the share of electric vehicles to 50% by 2030 [78]. Singapore plans to develop 60,000 charging points at public car parks by 2030 [79]. These commitments made at various global fora, including NDCs pledges, need to be translated into actions.
The review of the efforts to date show that Asia is leading on many fronts: the adoption of low-carbon transport strategies; the development of mass transit systems in cities; a shift to renewable energy resources and electric mobility; and prioritizing active mobility. However, emissions in the transport sector continue to rise. The core question, therefore, is: how can Asian countries accelerate mitigation actions in the transport sector?
The onus of implementing comprehensive low-carbon pathways that are aligned with NDC commitments rests with national transport authorities and institutions. Although countries and cities have implemented various policies to reduce emissions from their transport systems, these efforts have not delivered the anticipated results; as noted above, only three Asian countries have reduced emissions to date. Carbon accounting approaches could be useful to track the progress and to refine strategies as necessary. GHG are one of the indicators of the sustainable urban transport index [80,81], and the guidelines [82,83] provide a simple approach to assess GHG emissions from transport operation.
Some of the commitments made by developing countries in the NDCs are tied to international support. The scarcity of financial resources should not lead to a "take what is on offer" approach. Rather, available national resources should first be mobilized to priority areas, and then nations should seek to augment financing with international support. Authorities could also explore innovations and low-cost mobility options.
COVID-19 has taught us to think and do things differently. Technology applications such as virtual meetings and working from alternate locations have helped to reduce travel demand in the short-term. It also highlighted the need to integrate health and environment into urban and transport planning [84].
While it is difficult to prescribe a one-fit-all strategy, this review suggests that future transport polices should have clear linkages to NDCs, including measures to "green" the growing fleets of two and three wheelers and informal modes of transportation; improve the accessibility of public transport; improve coordination, urban governance, and accountability of transport institutions [85]; consider low-cost solutions, new technologies and innovative approaches [86]; integrate land use and mobility policies [87]; and advocate changes in user behaviour.

Conclusions
A review of the efforts of Asian countries and cities towards reducing emissions and enhancing the sustainability of urban transport systems was presented. Some policies being Earth 2021, 2 742 pursued are the promotion of electric mobility, enhancing the accessibility of mass transit, shifting to renewable energy, a modal shift away from private vehicles, and the promotion of active mobility. Even though Asian countries are leading on many fronts, the overall emissions from transport increased by 41% during 2010-2019 in Asia. The improvement of public transit, the use of renewable energy, electric mobility, and the prioritization of walking and cycling are some of the transport strategies included in the NDCs. There was some air quality improvement in Asian cities in 2020, which was mainly due to the traffic operation restrictions implemented during COVID-19. However, the existing PM2.5 values far exceeded the WHO standards in all cities. The number of vehicles per 1000 inhabitants is also increasing in Asian countries. Only Singapore has reduced its vehicle population. The high share of powered two and three wheelers in many countries in South and South East Asia adds to congestion and safety problems. The informal transportation methods in many Asian cities complement formal public transport systems, so initiatives to enhance the efficiency of informal transport should be continued.
The improvement of public transport is progressing in Asian cities. However, there are still issues with service and fare integration. There has been a shift to using private vehicles, cycling, and walking during the COVID-19 pandemic. This has prompted a redefinition of "sustainable mobility" to include safeguarding long-term ecological sustainability, health, and wellbeing, satisfying basic transport needs, and promoting intra-and intergenerational equity [88]. Improvements in the walking and cycling infrastructure, and increasing the surrounding environment with green space and interconnected parks, would create more livable and walkable cities.
In order to achieve the commitments made in the NDCs, decarbonize transport by 2050, and deliver on climate action, strong collaboration among transport stakeholders as well as other related sectors such as energy, manufacturing, and infrastructure will be necessary. The NDCs and other commitments need to be translated into a comprehensive low-carbon mobility strategy based on the avoid-shift-improve framework. It is also important to track the impacts of projects and strategies on emission reductions. A simple carbon accounting approach can be useful to make informed decisions and further refine strategies.
While the current paper mainly focused on the mitigation of emissions in the transport sector, national efforts are also necessary to strengthen resilience and to enhance the adaptive capacity of countries. Guidelines are available on planning, adaptation, and resilience measures [89][90][91]. National strategies should aim to enhance the capacity of transport infrastructure and systems to withstand the impacts of climate events, as evidence shows that they are becoming more frequent and intense.

Acknowledgments:
The author acknowledges the support provided by Srishti Slaria for the literature review. The views expressed in this paper are those of the author and do not necessarily reflect the views of the United Nations. The author would like to thank the three anonymous reviewers for their comments and feedback that has helped to refine the paper and Fuyo Jenny Yamamoto for her support in editing the paper.