As reported on October 5, 2020, Delhi is inching towards an air pollution spike, with winds slowing down and the mornings getting colder. As the winds in the city become calm and the minimum temperature drops air quality in the national capital begins to dip from October onwards every year. the problem is compounded by stubble burning in neighbouring states.
According to the air quality early warning system under the Union Ministry of Earth Sciences, air quality was likely to be ‘moderate’ when the air quality index (AQI) was between 101 and 200 on October 5 and 6. However, stubble fire points were observed over Punjab, adjoining Pakistan, Haryana, as well as Uttar Pradesh are increasing over time which may adversely impact Delhi and the National Capital Region’s air quality.
Winds in this region travel mainly from the northwest at this time at speeds of up to 14kmph and skies are mainly clear. Nights and early mornings are getting colder, and wind speeds are reducing in the evening and early morning. The minimum temperature is expected to hover around 18 to 19°C, but maximum temperatures will be moderate, around 35 to 36°C. Pollutants do not disperse easily when winds slow down.
As per the head of the regional weather forecasting centre, there are clear skies after the monsoon has withdrawn. Day temperatures are high, but the heat is radiated back, so nights are cooler. The wind direction has changed from easterly during monsoon to north-westerly so the winds are blowing from the colder regions such as Jammu and Kashmir; Himachal Pradesh etc. If there is any rain or snow due to western disturbance, it will get colder.
The AQI is in moderate category. The ventilation index was approximately 12,500m2/s in the reported period. The ventilation index is a product of average wind speed and mixing height, and a value on the scale lower than 6,000m2/s, with average wind speeds lower than 10kmph is unfavourable for dispersion of pollutants.
Measures Needed to control pollution
State governments will have to take action on crop stubble burning. There are both in-situ and ex-situ options available to manage straw. The Centre has given funds to subsidise stubble management machinery. Subsidy of 50 per cent is being offered to individuals who buy the machine and 80 per cent to cooperative societies or panchayats.
Graded Response Action Plan (Grap), drawn up in 2017, defines specific measures to tackle different levels of air pollution. The Supreme Court-mandated Environment Pollution Control Authority (Epca) is in charge of enforcing the Grap measures. When air quality hits ‘poor’ levels, under Grap, garbage burning is monitored and fines are levied on those caught burning garbage, apart from measures to control dust, increased focus on polluting industries, and others. Meanwhile Citizens for Clean Air, a group of citizens, environmentalists, waste management experts appealed Epca to issue advisories or orders prohibiting the sale and use of firecrackers during the pandemic as it could aggravate public health issues, including Covid-19.
Courtesy: Hindustan Times