The air quality remained in the “severe” category on Sunday in Noida, Greater Noida, Ghaziabad, Faridabad and Gurugram in the National Capital Region.

Concentration of major air pollutants PM2.5 and PM10 also remained high in the five areas, according to the air quality index maintained by the Central Pollution Control Board. According to the agency’s air quality index or AQI, any reading above 100 on the scale of 500 is progressively unsafe for health. At 5 pm, the AQI was 421 in Delhi, indicating “severe” conditions in the Capital.

At 4 pm, the average 24-hour AQI was 434 in Gurugram, 456 in Ghaziabad, 440 in Greater Noida, 428 in Noida and 426 in Faridabad.

While the pollution control board uses 24-hour average data, the Ministry of Earth Sciences’ SAFAR, or System of Air Quality and Weather Forecasting And Research reports real-time figures. The government-run monitoring agency said the overall AQI struck 413 around 6 pm. Levels of the most dangerous particles, called PM2.5, climbed to around 305 micrograms per cubic meter, which is considered hazardous to breathe.

“The overall Delhi’s AQI has marginally improved to the higher end of Very Poor as of today morning,” SAFAR’s latest forecast said. “Surface winds have become calm, which were moderate so far, and forecasted to stay low in magnitude for the next two days. This is the major factor due to which no quick recovery is expected unless a drastic reduction in fire counts takes place. Air quality is forecasted to marginally deteriorate and stay at the severe to the higher end of a very poor category for the next two days.”

PM2.5 and PM10 were the primary pollutants in the cities adjacent to Delhi. Particulate matter smaller than 2.5 microns (or about a ten-thousandth of an inch) is particularly dangerous to human health. Such particles are small enough to travel deep into the respiratory system, potentially impairing lung function. To be considered safe, the National Ambient Air Quality Standards require PM2.5 concentration to be less than 60 micrograms per cubic metre of air in any given 24 hour period.

The air quality for every city is based on the average value of all stations. Ghaziabad, Faridabad, and Noida have four stations each, and Gurugram has three and Greater Noida has two.

On Sunday morning, the AQI remained in the severe category for the fourth straight day with the index marking it at 405 at 7 am, according to the Hindustan Times. Delhi’s average air quality stood at 450, 406, and 427 on Thursday, Friday, and Saturday.

“For the last three days we have been observing that the number of farm fires spotted over Punjab alone is over 4,000,” VK Soni, the head of the weather department’s environment monitoring research centre. “Usually, these fires go up on Sundays at this time of the year. Though the wind speed picked up during the day, the improvement in air quality was not all that significant only because of an uptick in farm fire cases.”

India Meteorological Department’s regional weather forecasting centre head Kuldeep Srivastava said that wind speed in parts of central Delhi fluctuated between six and eight kmph on Saturday. Wind from the north-western direction brings a large share of smoke from Punjab and Haryana, he said, according to the newspaper.

Delhi’s air pollution typically worsens in October and November due to farmers burning off stubble in neighbouring states, unfavourable wind speed and traffic fumes in the city. Firecrackers ignited for Diwali adds to the problem.

This year’s haze comes as the Capital is battling a new surge in coronavirus infections, and health experts fear that people with chronic medical conditions could become more vulnerable to the disease. On Friday, the health ministry informed a parliamentary committee that air pollution may lead to faster spread of the coronavirus infection, as it causes coughing and sneezing.

Last month, the Indian Council of Medical Research had also said, citing international studies, that air pollution levels can lead to rise in coronavirus mortality. Delhi has been reporting over 6,000 new coronavirus cases for the last few days.

The Supreme Court on Friday directed the Centre to ensure that there is no smog in Delhi and National Capital Region amid heightened alarm over the health hazard posed by it during the coronavirus crisis.

Also read:

  1. Ensure there is no smog in Delhi: SC tells Centre’s new air quality commission
  2. Air pollution may lead to faster spread of Covid-19, health ministry tells parliamentary panel