Delhi’s AQI ‘very poor’ at 290 on Sunday evening, no major relief likely

Delhi and its suburbs recorded a marginal improvement on Sunday, although a major relief is unlikely in the coming days, regulators said.

The city’s air quality index (AQI) stood at 290 at 7 a.m. but had deteriorated to 301 by 4 p.m.

The average 24-hour AQI, measured at 4pm each day, was 319 on Saturday, 405 on Friday and 419 on Thursday.

Neighboring Ghaziabad (280), Gurugram (234), Greater Noida (236), Noida (268) and Faridabad (327) also recorded “poor” to “very poor” air quality.

An AQI between zero and 50 is considered good’, 51 and 100 satisfactory’, 101 and 200 moderate’, 201 and 300 poor’, 301 and 400 very poor’, 401 and 450 severe’ and above 450 severe plus’.

The Center on Saturday lifted strict restrictions, including a ban on construction work related to linear projects and entry of polluting trucks into Delhi, in view of the decline in air pollution due to favorable wind speed and direction.

These measures form the final phase – Phase IV – of the Centre’s air pollution control plan, called the Graded Response Action Plan (GRAP).

The Commission for Air Quality Management in National Capital Region and Adjoining Areas (CAQM), a statutory body responsible for formulating strategies to combat pollution in the region, has asked the states of Delhi and NCR to withdraw all emergency measures, including only CNG, electricity and BS. VI compliant vehicles from other states are allowed to enter Delhi, with exceptions for those engaged in essential services.

As per the latest CAQM order, all medium and heavy trucks not engaged in essential services in the capital were also banned under Phase IV of GRAP.

The pollution control agency said all other restrictions under phases I, II and III of GRAP, including a ban on non-essential construction, mining, stone crushing and diesel generators, will remain in place.

The air quality forecasts from the India Meteorological Department/Indian Institute of Tropical Meteorology do not indicate a sharp deterioration in the overall air quality of Delhi-NCR in the coming days, the CAQM said.

Recent findings from a joint project between the Delhi government and the Indian Institute of Technology (IIT), Kanpur, showed that vehicle emissions were responsible for about 45 percent of the capital’s air pollution on Friday. On Saturday this dropped to 33 percent.

Secondary inorganic aerosols – particles such as sulfate and nitrate that are formed in the atmosphere due to the interaction of gases and particulate pollutants from sources such as power plants, refineries and vehicles – are the second leading cause of Delhi’s air pollution, accounting for 19 to 36 percent of the city’s air pollution in recent days.