Written by By Jack Boyle, CNN
The Indian capital’s air is still very poor, according to a pollution monitoring data released this week, despite the city taking action to deal with the worsening situation.
Despite the Delhi government putting in place emergency measures including a ban on construction, an increase in central heating and the use of cleaner diesel-powered vehicles, air quality did not improve — albeit at a slower rate.
Below is an overview of the data released by the Air Quality Index, which is maintained by environmental watchdog the Central Pollution Control Board. It gauges the concentration of fine particulate matter, known as PM 2.5, and fine particles , known as PM 10, less than 2.5 micrometers in diameter, or around one hundredth the width of a human hair.
Air quality in Delhi has been extremely poor since April
Above an index value of 100, the air has been described as “very poor,” while between 101-200 puts the air at “hazardous” level.
However, the latest data indicates that air quality in Delhi has improved in the last two weeks, falling below 100 with an index value of 100.3 on November 28, the last date for which data is available.
A few days later on December 2, Delhi hit a new “very poor” level, down to 101.6.
A temperature shift, which has seen pollution levels rise over the last two weeks, have been partly explained by some of the above measures.
When high atmospheric pressures over the city push pollution to the north, they can lessen the effects of prolonged periods of cloud formation, which increases rain and this falls on air and soil containing pollution particles. This weather change allows rain to fall, and for this to sink and dilute the pollution.
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This week, however, the Delhi government imposed a nationwide ban on diesel-powered vehicles and ordered construction work suspended, just one of the emergency measures.
Air quality has continued to worsen, according to the CPCB’s data, despite the temporary measures taken by the city government.
“In the past, the municipal authorities and the central government have taken strenuous measures — the temporary closure of schools, power conservation and special fireworks,” said S. C. Gupta, Chairman of the CPCB.
“However, there seems to be a dearth of holistic policies.”
It is a theme echoed by the Civil Aviation Ministry, which has written to the country’s prime minister, Narendra Modi, expressing concern about the impact of air pollution on the country’s top-ranked aviation hub, according to an environment ministry official cited by CNN-IBN .
According to the Indian government, 1,200 “very poor” days were reported between April 1 and June 30, with 1,032 emergency measures ranging from “state of emergency” to “holiday” decrees.
This year, air quality is projected to be worse than the sub-zero winter months of November and December, with annual air quality levels not expected to improve until 2020.
In the meantime, Delhi faces a long wait for the weather to change to get back on track.