By A.K. Jain, former Commissioner – Planning, DDA, and member of Global Human Settlement Network UN Habitat
Motorization in South Asia is contributing to an increase in transportation energy intensity and consumption of fossil fuels. The 
impacts of oil-based transport energy on the natural environment (energy and mineral extraction and use, hydrological cycle and water quality effects, consumption of agricultural land and natural habitats through urban sprawl, air pollution, etc.), and the built environment (noise, pollution, traffic accidents, community severance) are significant. In several cities of South Asia, e.g., Delhi, 72 per cent of emissions (suspended particulate matter) are due to motorized vehicles. The International Council of Local Environmental Initiatives (ICLEI) states that on an average 24 per cent emissions are from urban transport. These are likely to rise steadily due to the growing city size, rising incomes, high motorization and to inefficient engines and fuel use.
In Iran pollution from vehicles in large cities is a serious problem. It is estimated that 4,000 people die every year from air pollution-related diseases in Tehran. To reduce demand for refined fuels and to lower air pollution, the Government is seeking to introduce compressed natural gas vehicles.
Dhaka has become one of the most polluted cities in the world. The city environment has been deteriorating rapidly during the last four years. Complaints about headache, eye and skin irritation as well as breathing problems are common among the residents of the city. The situation is feared to worsen with the population increase, its mobility and economic development. In Dhaka, the concentration of oxides of nitrogen, oxides of sulphur, carbon monoxide and suspended particulate matter are 500, 1,200, 7,500 and 2,500 µgm/m3 respectively which far exceed the acceptable limits set by WHO.
The car is the main contributor of sulphur, nitrogen and carbon monoxide emissions in the city. The contributions from buses and trucks are significant in the case of sulphur and nitrogen emissions. Auto-rickshaws and two-wheelers contribute significantly to sulphur and carbon monoxide emissions.
According to the Department of Environment and the Bangladesh Road Transport Authority, more than 90 per cent of the vehicles in Dhaka are faulty and emit smoke far exceeding the prescribed limit. The Bangladesh Atomic Committee reports that automobiles in Dhaka emit 100 kg of lead, 3.5 tonnes of suspended particulate matter, 1.5 tonnes sulphur dioxide, 14 tonnes of hydrocarbon and 60 tonnes of carbon monoxide every year. To make the city environmentally sustainable and to cleanse the air, initiatives are being taken to assess the level of air pollution, introduce technology and institutional reforms and make use of cleaner fuels mandatory to control emissions from motorized transport.
Emissions vary widely as per the mode, which is as high as 4.5 metric tonnes per capita for those using private motorized transport. This is expected to double within the next 10 years if private motorized travel continues to grow at the present pace of 8-10 per cent per year in the absence of remedial measures. Studies show that to transport one ton of cargo per km, road transportation needs four-five times the energy that is needed by a train. The energy used by a car to carry a passenger over one km is three-four times that of a bus.
Greenhouse gas emissions per passenger of public transport (bus, rail and trams) is about one-twelfth that of a car (table). Although NMTs (including walking) are ideal from the point of view of emissions control, in terms of km travelled, these cover only one-two per cent of the total vehicle km travelled, even if the proportion of trips are as high as 40-50 per cent, as in Delhi and other mega cities.
Various policy initiatives have been taken by the South Asian countries to deal with the environmental sustainability of transport. These include improving the environmental efficiency of vehicles such as engine/performance; fuel type and quality, to ensure low pollution fuels; improving emissions and environmental regulations; and improving the quality of road infrastructure and public transport.
In Mumbai, Delhi and other cities in India, air quality improvement efforts include adopting CNG, LPG and other cleaner fuels, 
improving engine standards for fuel efficiency, vehicle and road maintenance and strengthening of public transport (BRT, Metro, etc.). Likewise in Pakistani cities, Colombo and Dhaka, CNG technology, mandatory replacement of two-stroke engine, vehicle pollution checks, traffic reforms, etc., have been attempted.
The Strategic Action Plan of Maldives (2009-2013) includes the establishment of a nation-wide transport system with the idea of becoming the first carbon-neutral country in the world within a decade. A study on Urban Transportation and Environment in Kathmandu Valley, Nepal, emphasizes the need for formulating a comprehensive policy accompanied by a set of practical counter-measures which cover all major components of the activity-structure-intensity-fuel framework. It underscores that small, pro-active and upstream counter-measures such as managing travel demand, promoting a modal shift towards public transportation and progressive tightening of emission standards will reduce the pressure and mitigate emission. It is estimated that such a package will reduce carbon dioxide emissions by 20 per cent and energy use by 18 per cent.
Empirical data indicates that vehicular pollution loads have significantly reduced in cities like Delhi, with improved engines and fuels, in terms of emissions per vehicle kilometre travelled by cars and 4-stroke two- and three-wheelers. But the problem is mainly with the exponential growth of vehicles, travel demand and urban sprawl. Therefore, the challenge is to reduce the vehicle km travelled and trip length by travel demand management, land use policy, etc.
Impacts and challenges
In most South Asian cities sustainability of surface transport system is constrained by three distinct sets of factors. These are physical (e.g., conversion of agriculture/forest for urban use and transport network, environmental impacts, periodic flooding, poor soil condition, siltation and erosion of rivers, etc.); low investments in public transport systems; and inadequate institutional framework.
The environmental dimension of transport projects often remains disjointed. In practice it means vehicle and fuel-centric environmental controls such as checking of ‘pollution control certificate’ of vehicles and fuels. In most of the cities there is hardly a comprehensive and legally enforceable system to evaluate and obviate the impacts of urban growth and transportation infrastructure projects (like expressways, flyovers, etc.).
Production and ownership of private motorized vehicles are being promoted with government support by the automobile industry, media and aggressive marketing, as well as due to poor alternatives to travel and transport goods. Overemphasis on transportation hardware such as more and wider roads, grade separators, fuels, engine efficiency and reduction of energy use have marginalized the software of environmental sustainability of transport, such as promoting walkable city, mixed land use, higher density, compact and smart growth, all of which reduce the demand to travel.
Planning interventions and non-invasive, non-structural solutions such as promoting transport and land use integrity and a walkable city structure are hardly adopted in practice. Popular solutions like widening of roads, construction of flyovers/grade separators and mega transport terminals are pursued by transport organizations and political leadership that consider these as a matter of prestige and professional achievement. However, these often prove to be short term and sometimes even worsen the situation.
Integrity between transport and urban planning, along with transport demand management, transportation mode and technology choice are crucial factors in transport sustainability. It implies a change in perspective as public transport and NMTs are usually seen as the mode for the not so well-off section of the community who cannot afford to own/use personal transport. To change this perception public transport and NMTs have to be reinvented as in Dhaka where Volvo buses were introduced. Luxury air-conditioned buses have also been introduced for city transport in some Indian cities such as Delhi, Mumbai, Bangalore, etc., which helped in changing the perceptions of public transport. In Agra, state-of-the-art designer rickshaws have proved more efficient and less polluting.
Apart from aspects like reliability, frequency, inter-modal integration and single ticketing systems, the quality of public transport would need to be significantly upgraded, inter-alia, keeping in view the elements of clean and non-carbon (green) fuels and traffic calming. This way a reduction in use of fossil fuels for pollution control is linked with public transport sustainability, efficiency and performance. Some cities in India like Indore, Ahmadabad and Delhi have recently adopted Clean Development Mechanism protocols, performance standards and IT-based traffic management and passenger information systems for public transport.