Delhi’s air quality has deteriorated again with the arrival of winter, as the Indian capital’s Air Quality Index (AQI) rose above 300 and entered the “very poor” category. Authorities have activated the second phase of the Graded Response Action Plan (GRAP) after forecasts indicated that pollution would remain at very poor levels over the next few days.
Emergency measures introduced
GRAP is a set of emergency measures that become progressively stricter as pollution worsens. The latest measures target dust, vehicle emissions and other pollution sources through more intensive street cleaning, higher parking fees to discourage private car use and expanded public transport services.
Delhi Metro will add 20 train services on weekdays. Authorities have also been directed to stagger the working hours of government services to help reduce traffic congestion.
Delhi’s AQI was 377 on Wednesday morning. India’s air pollution monitoring agency classifies readings from 301 to 400 as “very poor”, while readings above 400 are considered “severe”.
Health risks and seasonal pollution
Long-term exposure to heavily polluted air can cause respiratory illnesses or worsen existing conditions. Children and older people are particularly vulnerable.
The AQI measures eight major pollutants, including PM2.5. These particles are about 1/30th the width of a human hair and can travel deep into the lungs.
Delhi and neighboring areas of northern India face hazardous air every winter, with conditions often worsening around Diwali, one of India’s biggest festivals, which is just days away. Although the festival is celebrated with lights and lamps, fireworks can release particulates and harmful gases, further degrading already poor urban air.
The annual pollution crisis has several causes, including vehicle exhaust, industrial emissions, falling temperatures, weaker winds and the burning of crop stubble in neighboring states.
Weather and crop burning add to the problem
October was unusually clean overall, with Delhi recording its lowest average AQI for the month in eight years, but pollution then increased sharply.
Experts attributed the sudden deterioration to lower temperatures, slower wind speeds and increased crop-residue burning in the neighboring states of Punjab and Haryana.
Recent storms brought rain and strong winds that temporarily cleared the air. As conditions became calmer, however, northwestern winds returned and carried smoke from burning fields toward the capital.
Source: www.bbc.co.uk
