This article is more than 1 year old

This article is more than 1 year old

Pollution in Delhi has reached its worst level this year in the past two days, prompting authorities to rate conditions as “severe to emergency”, which indicates the potential for a public health crisis.

Senior government officials said the main reasons for the increase in smog were unusually cold air, fog and a lack of wind.

Such conditions trap vehicle fumes and pollution from coal-fired power plants, industry and domestic fires over the city.

Data from the government’s Central Pollution Control Board (CPCB) showed the air quality index, which measures the concentration of poisonous particulate matter, was an average of 449 on Monday, only slightly better than 450 on Sunday.

The index measures the concentration of PM 2.5, particles that can be carried deep into the lungs. The previous highest recording this year was 447 on 15 June, when there was a dust storm. Anything above 100 is considered unhealthy.

India’s weather department said the index reached 654 in some parts of the city, and visibility was down to as little as 200 metres.

Environmentalists said the authorities’ inaction was inexcusable and a concerted effort was needed to reduce pollution from vehicles and industry.

“If this is not an emergency, then what is?” asked the Delhi-based environmentalist Vimlendu Jha.

The “severe to emergency” rating means the air is not only hazardous for citizens with existing respiratory problems but can also seriously affect healthy people.

Could a grid of giant filters help clean up Delhi's polluted air? Read more

Conditions are likely to remain severe on Christmas Day, when CPCB data suggests the PM 2.5 level may average above 400 and reach a high of 534 in some places.

CPCB announced measures such as shutting factories and construction sites in heavily polluted areas until Wednesday, along with advising people to avoid using diesel-powered vehicles.

Steps this year have failed to make much difference and instead there has been finger-pointing between Narendra Modi’s administration, the city government and state authorities around the capital.

The public’s apparent lack of concern about air quality gives federal and local politicians the cover they need for failing to address the problem, according to pollution activists and social scientists.

India’s toxic air killed 1.24 million people in 2017, said a study published in Lancet Planetary Health this month.