How to Reduce Smog in India’s Cities

New Delhi now has the dubious distinction of being the world’s most polluted city, at least, if you look at the concentration of the especially hazardous small particulate matter PM 2.5. It is (un)safe to say: Delhi has overtaken Beijing in terms of smog.

The World Health Organization states that a concentration of PM 2.5 above 25 PPM (parts per million – a measure of how many particles there are in the air) is unhealthy. The annual average should not exceed 10 PPM. Many European cities typically lie between 10-20 PPM. Beijing has, on average, around 100 PPM. In Delhi, the 2014 average was 140 with peaks reaching 350 or even more, values that are quite literally “off the chart”.

A recent study by Harvard University has shown that of the 20 cities with the highest concentration of PM 2.5, 13 were in India.

This has serious health implications. The suspended fine particulate matter in the air is so small that it enters the capillaries of the lungs and from there into the bloodstream. It can cause heart attacks, strokes and cancer – in addition to the respiratory illnesses.

Researchers have calculated that India’s polluted air takes an average of 6 years of peoples’ lives. When US President Barack Obama came to visit Delhi in January 2015, American newspapers were half-seriously speculating how many hours of his lifetime the visit would cost Obama.

Smog: Causes and Cures

The causes of the air pollution are several. Weather matters. The cold, windless winter sometimes traps the air in the city. Interestingly sunshine also plays a role: it adds energy to the gas mix in the air, setting in motion chemical reactions that can create the heavy smog that we sometimes witness. Of course, the fact that the population and economies of India’s cities are growing fast compounds the problem.

But how does the air get polluted in the first place? There are three main culprits.

The first is pollution from industry and the burning of fossil fuels, biomass and waste. The second is pollution from vehicles. A third is agricultural practices, such as the burning of fields around the cities.

Air pollution, by the way, is not only a local phenomenon. In China, the rapid industrialization has created an entire black belt of pollution covering large parts of the country and reaching into neighboring Russia, Japan and Korea. Acid rain “made in China” has been witnessed as far away as California.

The West has Done it – India can, too

The good news is: air pollution levels can be brought down. In the 1950s and 1960s, many European and American cities, such as London and Los Angeles, were shrouded in heavy smog. They have become much cleaner since. So the high levels of air pollution seen in Indian cities are by no means inevitable.

Urban Planning and Regulation can go a Long Way

Urban Planning is one important lever. More public transport helps reduce the number of cars. Also, peripheral highways around the main cities can divert a lot of the freight traffic away from the city. Such roads are currently being built in Delhi. Building the infrastructure for fuel switching is also crucial: Compressed natural gas (CNG) stations and plug points for electric vehicles should be made available to encourage low-emissions modes of transport. Also, it would help greatly, if coal-fired power were replaced with renewable power generation, even rooftop solar PV.

Regulation is more powerful still: state-of the art air filters need to be added to all industrial and power plants. The same should go for vehicles. Public transport and taxis should be forced to switch from petrol to cleaner fuels. In Delhi this has been done already to CNG. Also, the agricultural practice of the burning of fields needs to be stopped. Importantly, it is not enough to have regulations. They also need to be rigorously implemented and enforced.

If these measures are taken, there is no reason why India city dwellers should not be able to breathe easy again.


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Tobias Engelmeier
Tobias Engelmeier
Tobias Engelmeier is an entrepreneur and very passionate about the climate, sustainability, solar energy and India. He is a German Indophile. You can find out more about Tobias on and on LinkedIn. He is also active on Twitter (@TEngelmeier).
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