What was the Great Smog of London, such an orgy occurred, thousands died in a few hours, how did we get rid of air pollution?

Exactly 71 years ago in December 1952, London was covered with such a dense fog that visibility was reduced to less than a meter. The air became so black and suffocating that people started dying. Even today the people of England are unable to forget that incident. It is called the Great Smog of London. This resulted in the deaths of approximately 4,000 to 12,000 people. This smog was created due to the use of coal which spread a thick black blanket over the entire city. This smog did not last for one or two days but started from December 5 and continued for the next five days i.e. till December 9, 1952.

These occurred mostly in winter and were a worse example of year-round air pollution. This story will sound familiar to anyone living in the Ganga plains and especially Delhi. Four years later a new Clean Air Act was passed. High-sulphur coal, which causes the most toxicity, was the first to be banned. With time, coal heating was replaced by gas. Power plants and polluting factories in the city were cleaned up or closed and production was moved further away. Due to gas being abundant in the North Sea, it almost completely replaced coal.

As medical evidence grew, sulfur scrubbing and unleaded petrol were introduced during the 1980s. A clean diesel program was initiated in the 1990s to reduce particulate matter. Diesel as a fuel was promoted for its fuel efficiency, before the policy began to be reversed around 2010. Euro emissions standards began in the 1990s with the latest Euro VI standards, which mandated emissions that were less than one-tenth of Euro I standards.

Recently London has promoted clean air zones. At the local level these are about speed restrictions, banning vehicles from idling and other such actions. These are focused on schools, hospitals and similar facilities where local pollution levels are a concern. Broadly speaking, since 2009 the whole of London has been covered by a policy of low emission zones which restricts heavy polluting vehicles. And an ultra-low emissions zone banning all polluting vehicles has been implemented in central London since 2019 and expanded in stages to cover the whole of London. Apart from these, all other sources of pollution, such as wood fires, are being dealt with through action plans

What is different in India?

The evidence base in India is more vague but clear enough to require serious action. According to an estimate, 1.6 million people die every year due to air pollution. This figure is three times the official number of Covid deaths. So where is the Covid-like urgency to act on this? Actions taken in the UK and elsewhere provide some clues as to what needs to be done in India, but there are also some important points of departure. Despite vigorous debate over crop burning or Diwali firecrackers, it is road dust that accounts for half of the suspended particles throughout the year. This is an insignificant issue in London, so cleaning the streets requires a different kind of response. Only once we overcome road dust do all other pollutants come into effect. The major component in the remaining half is still vehicle pollution. Although studies in India do not distinguish between tailpipe emissions and tire and brake wear, evidence from other countries suggests that about half of particulate emissions do not come from the tailpipe. India’s experience may lead more towards the tailpipe due to the type of vehicles and their maintenance, but it is still the case that even if we went to a fully electric fleet we would still have a larger share of emissions.