Smog has also led to numerous school closures and flight cancellations in India’s capital and largest city. It has also been blamed for highway accidents.

Delhi is home to 20 million residents, and the city’s more than 10 million vehicles are a major contributor to air pollution. Industrial emissions are also to blame. Thirteen coal-fired power stations operate within a 300km radius of the city. Conditions reach crisis level every winter, when the capital’s already poor air quality is further degraded by smoke from post-harvest burning in the neighbouring agricultural states of Haryana and Punjab.

The concentration of airborne particulate matter (PM2.5) recently reached 999 in parts of Delhi. This measurement was literally off the charts of maximum thresholds for air pollutants.

The alarming fact is that Delhi is not even India’s smoggiest city. By one measure, four other Indian cities typically suffer even worse air pollution.

There is little evidence that either the central or Delhi government has any effective policy strategy for air pollution. Now is the time for India to peer through the smog and learn how another major city, Beijing, is taking meaningful steps to stabilise its own air pollution crisis. While China still has progress to make, some lessons from the country’s capital are a useful guide for clearing Delhi’s air.

According to the World Health Organisation, ten of the world’s 20 most polluted cities are in India, and three in China. The two countries top the ignoble list of deaths related to air pollution, with more than one million each in 2015. The two are the world’s most populous countries and also have among the highest proportions of deaths related to air pollution.

Nevertheless, China is making progress. The central government has taken a systematic and coordinated approach to managing air pollution. It has adopted a suite of policies that promote alternative energy and punish regulatory breaches.

The country is rapidly scaling back capacity for coal-fired power and steel, whose production is suspected of threatening respiratory health. China is also soliciting foreign investment in green energy technologies, and has intensified inspections of major polluters around Beijing.

In Beijing alone, fines for pollution topped US$28 million in 2015. To combat vehicle exhaust smoke, which is responsible for one-third of Beijing’s emissions, an annual quota of 150,000 new cars was established for 2017, with 60,000 allotted only to fuel efficient cars. Beginning in 2018, this quota will be reduced by one third, to 100,000 annually. This will limit the total number of cars to around 6.3 million.

Beijing is also aiming to reduce coal consumption from the current 11 million tonnes per year to under 5 million by 2020.

There is some evidence that these measures are working. In the Beijing-Tianjin-Hebei region, PM2.5 levels decreased by 27 percent between 2013 and 2016.