In the past few months air pollution in Delhi has become a major concern once again. Last December the National Green Tribunal issued orders that overloaded trucks should not be permitted in Delhi, vehicles more than 15 years not be permitted to ply in Delhi, and vehicle parking on the main roads or any metalled roads be prohibited. Other suggestions include limits on registration of cars in Delhi, imposition of congestion charges in central Delhi, banning burning of leaves and other material, and use of mechanical cleaners instead of manual sweeping of streets. Though most cities in India, small and big, see similar pollution levels as Delhi, our concerns for people’s health limits itself to the capital city of India. If this were not so, the above directions would have been issued for all of India. This is not the first time that heavy-handed measures are being pushed in Delhi. In 1995 the Supreme Court ordered the closure and relocation of polluting industries in Delhi. In this instance the Court responded to middle-class appeals for pollution reduction and adversely affected tens, even hundreds, of thousands of the city's poorest workers. In 2001 the Court ordered the closure of all polluting and non-polluting industries that were located in residential areas but did not conform to the Delhi Master Plan. And, in 2002 it ordered the preparation of a scheme for compulsory switchover to CNG/LPG as automotive fuel for all public transport vehicles. After all these measures Delhi’s air has eventually become worse than before. This experience should make us pause and think. Where have we gone wrong? Why is it that a city like Delhi which has fewer cars per thousand persons than Singapore, London or Paris and has fewer industrial units than most European or Japanese cities have much dirtier air? The answers are not easy to get, and may not be very palatable. One of the problems is that many of our policy options are based on very unreliable data. For example, the Delhi administration informs us that there are about 5.6 million two-wheelers and 2.7 million cars registered in Delhi. This gives us an average of about 2.5 vehicles per family — a number impossible at our levels of income. We at IIT Delhi investigated this issue in detail by examining age of cars and two-wheelers coming to petrol pumps and pollution check stations, and samples of vehicles on the road.1 Our results are surprising: only 59 per cent of the registered cars and 42 per cent of the registered two-wheelers are in use in Delhi, more than 65 per cent of the vehicles are less than 5 years old and less than one per cent more than 15 years old. The official numbers exaggerate the total number of vehicles in Delhi by almost a hundred percent, because no vehicles are ever removed from the list as we pay a lifetime tax and don’t need to register our vehicles annually. Obviously any emission calculations based on official statistics will be quite erroneous. It is not surprising therefore that estimates of sources of pollution differ so much from study to study. Recently, a detailed analysis of air pollution in Delhi by Guttikunda and Giuseppe taking into account all possible errors in official statistics gives us some interesting insights.2 Transport, brick kilns, industry power plants and domestic sources contribute similar amounts of small particles (PM2.5) to the atmosphere, the main contributors of SO2 are brick kilns, industry and power plants, and of NOx mainly transport, gen sets and industry. If these estimates are anywhere close to reality we will need a serious review of our policies. It is quite clear that construction (including brick kilns), industry and power plants contribute significantly to the quality of air: 50 per cent of PM2.5 and 89 per cent of SO2. The question of moving them away does not arise, as no matter where they are located they will harm human beings if operated in the same way. Neither can improvements come in a great hurry. There has to be a serious long-term policy for technological improvements with associated rule making and more stringent environmental standards. This will need a much greater investment in focussed research, development and innovation. According to these estimates, 78 per cent of NOx is contributed by motor vehicles and diesel gen sets. NOx is generated by oxygen and nitrogen in the atmosphere being heated together when anything burns and does not depend on quality of fuel. The higher the temperature of burning the more NOx you get.
Since diesel and CNG engines operate at higher temperatures (compared to petrol) they produce more NOx. This can only be controlled by reducing the need for diesel gen sets and equipping CNG vehicles with more advanced catalytic converters. The above analysis suggests that banning of cars more than 15 years old will not make any difference to air quality and just inconvenience a few retired people who own these cars. As far as the contribution of pollutants by motor vehicles as a whole is concerned, the present policies are unlikely to be very effective over the long term. The most effective policy would be one that can be governed centrally and has a permanent effect. The solution for this is clear — mandate the most stringent fuel quality standards as soon as possible for the whole country. Having different fuel quality standards for metro cities and the rest of the country is counterproductive. When metro vehicles are refuelled with inferior fuels their catalytic converters can get poisoned and become less effective. If we are serious about the pollution and health issue we should aim to impose Bharat V fuel and emission norms by 2018 and Bharat VI by 2021 and depend on piecemeal localised interventions. The policies that will actually make our cities healthier and better places to live in will have to be less car-centric. This was recognised many years ago even in USA. Richard Jackson, professor of environmental health science at the UCLA School of Public Health, claims “How we have built America is affecting our health, it’s also affecting our happiness, our prosperity, and our future. We have built it for the needs of cars and other short-term needs, maximising sale of commodity foods of various kinds and we have not built it with an eye towards people and an eye towards future generations”. The current development practices in urban India are still following age-old American practices. A permanent solution for reducing pollution is to reduce the need to travel long distances and make it possible for healthy persons to walk and cycle by choice. This won’t happen unless our streets are made much safer, going through mixed-use neighbourhoods and pleasant environments. People all around the world including India are discussing these issues. We are in an ideal situation and a point in history to take these discussions seriously.
1Goel, R., Guttikunda, S. K., Mohan, D., Tiwari, G., 2015. Benchmarking vehicle and passenger travel characteristics in Delhi for on-road emissions analysis. Travel Behaviour and Society 2, 88-101. 2Guttikunda, S. K., Calori, G., 2013. A GIS based emissions inventory at 1 km × 1 km spatial resolution for air pollution analysis in Delhi, India. Atmospheric Environment 67, 101-111. The writer is at the Indian Institute of Technology Delhi