What IIT scientists are not telling govt about air pollution
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NEW DELHI: There is something cyclical about the air pollution debate in Delhi - almost like the seasonal cycle of air pollution itself. When air pollution control slows down and the courts step in to demand action against the killer pollution, especially toxic vehicular fumes, the city gets swamped with 'scientific facts' to prove that all other pollution sources matter more than the vehicles. Instead of science becoming an enabler, it confounds action.
The stark evidence of this is the recent effort to counter the orders of the National Green Tribunal to ban 10-year-old diesel vehicles. A group of scientists from Indian Institute of Technology, Delhi, has shared scientific papers with the ministry of road transport and highways to argue that vehicles are a small part of the particulate problem and, therefore, action against a small number of old vehicles will have no impact. More than the specific issue of banning of old vehicles, which can be addressed with detailed strategies, this tendency to understate the gravity of vehicular pollution and its health risk has raised serious concern over scientific guidance.
What did our scientists fail to tell our government?
Firstly, the level of confusion is so high today because the pollution inventory and apportionment studies that assess relative contribution of different sources are looked at in isolation and not within a coherent framework of health protection. What ultimately should drive policy is not just what source is emitting more but which source is likely to lead to a greater exposure to health damaging pollutants. Globally, studies show vehicles contribute from a quarter to close to half of the particulates in cities. It is inexplicable why the ministry affidavit or the IIT papers have not included other studies and evidence that show high contribution of vehicles not only to particulates but also to other toxic pollutants and health risks. Comprehensive action on all sources does not mean lax action on vehicles.
Secondly, our scientists do not say that people are exposed to much higher health damaging pollutants than what occurs in ambient conditions. With each breath we inhale three-four times more pollutants than the ambient air concentration. Exposure to vehicular fumes is highest on road and up to 500 metres from there. The majority in our cities lives in that zone.
Thirdly, people are exposed to a mixture of pollutants whose combined effect has serious health impact. The benefits are greater when pollution sources are regulated for multi-pollutants. Delhi's air is thick with particulate matter, nitrogen oxides, ozone and air toxins. There is merit in NGT's focus on diesel emissions which is a multi-pollutant mixture classified as a class one carcinogen for its strong link with lung cancer. Exposure to toxins should be eliminated.
Fourthly, our air quality policies are cut off from the reported reality in the health sector. India is experiencing a rapid health transition, with a large and rising burden of chronic diseases, estimated to be more than half of all deaths and years lost to illness. Cancer, stroke, and chronic lung diseases are now major public health problems that are strongly influenced by air pollution.
Delhi has exhausted all soft options. Next generation air pollution control is about hard decisions. The city needs an implementation strategy before this winter to reduce traffic and vehicles, cut dieselization, scale up integrated public transport, facilitate walking and cycling, tax polluting modes, decide to implement Bharat Stage IV nationwide in 2015 and Euro VI in 2020 and put controls on other pollution sources. Our scientific community has an obligation to speak out on public health and enable the government to take strong action to reduce the health risk.
(The writer is executive director, research and advocacy, at Centre for Science and
The stark evidence of this is the recent effort to counter the orders of the National Green Tribunal to ban 10-year-old diesel vehicles. A group of scientists from Indian Institute of Technology, Delhi, has shared scientific papers with the ministry of road transport and highways to argue that vehicles are a small part of the particulate problem and, therefore, action against a small number of old vehicles will have no impact. More than the specific issue of banning of old vehicles, which can be addressed with detailed strategies, this tendency to understate the gravity of vehicular pollution and its health risk has raised serious concern over scientific guidance.
What did our scientists fail to tell our government?
Firstly, the level of confusion is so high today because the pollution inventory and apportionment studies that assess relative contribution of different sources are looked at in isolation and not within a coherent framework of health protection. What ultimately should drive policy is not just what source is emitting more but which source is likely to lead to a greater exposure to health damaging pollutants. Globally, studies show vehicles contribute from a quarter to close to half of the particulates in cities. It is inexplicable why the ministry affidavit or the IIT papers have not included other studies and evidence that show high contribution of vehicles not only to particulates but also to other toxic pollutants and health risks. Comprehensive action on all sources does not mean lax action on vehicles.
Secondly, our scientists do not say that people are exposed to much higher health damaging pollutants than what occurs in ambient conditions. With each breath we inhale three-four times more pollutants than the ambient air concentration. Exposure to vehicular fumes is highest on road and up to 500 metres from there. The majority in our cities lives in that zone.
Thirdly, people are exposed to a mixture of pollutants whose combined effect has serious health impact. The benefits are greater when pollution sources are regulated for multi-pollutants. Delhi's air is thick with particulate matter, nitrogen oxides, ozone and air toxins. There is merit in NGT's focus on diesel emissions which is a multi-pollutant mixture classified as a class one carcinogen for its strong link with lung cancer. Exposure to toxins should be eliminated.
Fourthly, our air quality policies are cut off from the reported reality in the health sector. India is experiencing a rapid health transition, with a large and rising burden of chronic diseases, estimated to be more than half of all deaths and years lost to illness. Cancer, stroke, and chronic lung diseases are now major public health problems that are strongly influenced by air pollution.
Delhi has exhausted all soft options. Next generation air pollution control is about hard decisions. The city needs an implementation strategy before this winter to reduce traffic and vehicles, cut dieselization, scale up integrated public transport, facilitate walking and cycling, tax polluting modes, decide to implement Bharat Stage IV nationwide in 2015 and Euro VI in 2020 and put controls on other pollution sources. Our scientific community has an obligation to speak out on public health and enable the government to take strong action to reduce the health risk.
(The writer is executive director, research and advocacy, at Centre for Science and
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