The National Capital Region of Delhi is not the only urban centre in the world to face an air pollution crisis. Many cities across the world have dealt with a similar problem at various stages of their development, and many have successfully resolved it.

Pollution levels peak in the winter months, as they have in Delhi in the past week. But according to Anup Bandivadekar, programme director of the International Council on Clean Transportation, major pollutants exceed safe levels through most of the year. In an interview to, he said that the situation isn’t just an air pollution emergency – it must be seen as a public health crisis that has persisted for several years in the North Indian belt, specially in Delhi.

Differences prevail over what the various sources of pollution are and how governments should prioritise addressing these sources. According to Bandivadekar, the way to prioritise action is not just to consider which source contributes the most to ambient air pollution levels, but to focus on which pollutants cause the greatest damage to human health on prolonged exposure.

Excerpts from the interview.

Anup Bandivadekar of the International Council on Clean Transportation. (Credit: @ICCT / Twitter)

What makes Delhi one of the most polluted cities in the world and how did we get here?
Delhi did not become one of the most polluted cities in the world suddenly. We have been approaching this notoriety for over a decade. We got here by initially refusing to acknowledge there was a problem with air quality, or imagining that if there was a problem it was in the eyes of the Western media and health experts, then by refusing to admit the harsh reality of health impact studies conducted by our own scientists, and thinking that we cannot afford to fix the air pollution situation lest it slow down economic growth.

Air pollution has reached crisis levels because the levels of fine particulate matter have exceeded daily national ambient air quality standards by a factor of 10 or more. However, we must remember that even during the rest of the year, levels of fine particulate matter in Delhi exceed annual national ambient air quality standards by a factor of 3 to 5, and nitrous oxide levels exceed annual national ambient air quality standards by a factor of 1.5. In reality, Delhi – and for that matter much of North India – has been in a state of air pollution emergency continuously for several years.

Why do you think India has not been able to handle the air pollution crisis so far?
To be fair, it is not that successive governments at the state and Central levels have not made any effort to alleviate air pollution. However, we must put those efforts in the context of the population and economic growth the country has experienced over this time period. They were simply insufficient, too little too late. Moreover, they were often in response to judicial interventions as opposed to proactive steps taken by the government. Even in cases where policy action has been taken, their enforcement has been lacking in most parts of the country. In addition, we have not engaged in the development and implementation of systematic and comprehensive science-based state and local-level air quality action plans. As a result, we lurch from one emergency to the next.

What are the transportation reforms we need in Delhi and why has the government failed to implement them so far?
The most fundamental transportation reform that has failed to materialise in Delhi is upgrading and expanding the bus network. Delhi needs twice the number of buses it has, perhaps even three times as many, if it is to maintain the modal share of buses [modal share is the percentage of passengers using a particular mode of transport]. And it should be expanding that share, not losing it to private transport. Whether for lack of funds or depot space, or arguments over whether they should be low-floor or not, the required buses have not materialised. In any case, improvement in bus transport is the single most important transport-related reform needed in Delhi.

In addition to more buses, protecting and enhancing the space for walking and cycling is key from the point of view not only of low emissions but of social equity as well.

In the case of vehicles, upgrading the inspection and maintenance practice from the ineffective Pollution Under Control regime to one that is based on remote sensing and on-board diagnostics will be important in keeping in-use emissions low. [In the current system, a computerised test decides if a vehicle meets emission standards and issues Pollution Under Control certificates that have to be renewed periodically].

Finally, Delhi may have to consider implementing low-emission zones where only non-motorised transport, buses and zero-emission vehicles are allowed. The political will for the implementation of such zones is not there yet.

The National Green Tribunal stopped the Delhi government from imposing odd-even car rationing last week. Do you think the odd-even scheme could have helped ease the current situation?
The odd-even scheme is now a part of the Graded Response Action Plan [a set of emergency measures to tackle air pollution]. As such, the scheme should be implemented when ambient PM2.5 concentrations exceed 300 micrograms per cubic meter for more than 48 hours. [A PM2.5 level of 60 micrograms per cubic meter is considered safe while any reading above 300 micrograms per cubic meter is categorised as severe]. The odd-even scheme by itself is unlikely to make a big dent in overall levels of air pollution in Delhi, but it can definitely lower peak concentrations when air pollution levels are at their worst.

For the National Capital Region specifically, what emergency steps should be put in place besides the odd-even plan?
Once again, the Graded Response Action Plan provides a reasonable template for actions that should be undertaken as air quality deteriorates. One can quibble about the specifics of the plan, but more attention needs to be paid to the implementation of the existing plan and even more importantly to figuring out how to lower the base level of pollution load in and around Delhi and the National Capital Region.

Does apportioning of source of pollution need to be definitive before governments can act or is there margin to act even as science and research evolves?
Of course not. There is no such thing as a definitive source apportionment study. All emissions inventories and source apportionments are the best estimates of the scientists at that point in time. These studies need to be carried out on a regular basis and should be used to refine our understanding of the air pollution situation and policy analysis over time. But there is no excuse for failing to take action to bring down air pollution even as we continue to refine our scientific understanding, especially when public health is at stake.

The biggest transport reform required in Delhi is an expansion of its bus network. (Credit: Raj K Raj / HT)

In Delhi there is a greater focus on vehicular pollution than other sources. Is that a correct thing to do? Could you explain the difference between exposure levels and ambient air quality?
Actions related to vehicular air pollution definitely receive a lot of public attention, but if you look historically, a number of actions have been taken on industrial sources. More recently, sources of air pollution – ranging from brick kilns to agricultural residue burning, power plants to garbage burning – have been scrutinised and actions taken to varying degrees of stringency and with varying success.

That said, focus on transport makes sense for a few reasons. One, exhaust from diesel vehicles (whether cars, trucks or construction equipment) is carcinogenic. Therefore, controlling diesel exhaust itself has to be a greater priority than to control, say, road dust.

Looking beyond the toxicity of the source of pollution, it is important to understand the exposure to a particular type of pollution. It is exposure to a pollutant that determines the health impact. However, attributing exposure to specific sources of pollution has traditionally been challenging, although advances in sensor technology is making it easier. By contrast, monitoring ambient air quality within a reasonable margin of error has been possible for some time, and thus the ambient air quality has been regulated as compared with exposure. Even if two sources of pollution contribute equally to the pollution load, it is possible that the human health effects of exposure to pollution from one source are much more serious than from the other. Vehicular emissions are closer to people than many other sources that contribute equally to the overall pollution load. This is especially true in the dense urban environments of India, where a majority of the population lives within a few hundred meters of major roads.

Is Delhi unique for the crisis it is facing or have other cities gone through the same crisis at some point of time, both in the developed and developing worlds? How did they address it?
While Delhi’s meteorological conditions and sources of pollution may be unique, its overall situation is no different than that experienced by other major metropolitan areas around the world. The south coast air basin of California in the United States or Jing-Jin-Ji (Beijing, Tianjin, and Hebei) region of China are examples of regions that have spent a lot of time and resources dealing with air quality. While air quality in the south coast basin is no longer at crisis levels, several parts of it are still in non-attainment with United States national ambient air quality standards. Jing-Jin-Ji’s fight with air pollution is more recent, but their efforts have started to show some early results.

Lessons from these places suggest that there are no silver bullets, nor is it possible to fix the air quality situation in a short duration. It takes a combination of public pressure, dogged scientific and technical work, coordinated policy effort across multiple agencies, and a strong political will to ensure compliance with regulations to make a big difference. There is a shortage on nearly all counts in Delhi at present, but there is no reason why Delhi cannot get its act together just like Los Angeles or Beijing did.