A new report by the World Health Organisation (WHO) on ambient air pollution levels shows that with very high levels of particulate matter measuring 10 microns or less, Delhi is among the most polluted cities in the world, second only to Riyadh among the big cities.
The report — Ambient Air Pollution: A Global Assessment of Exposure and Burden of Diseases — found that 92 per cent of the world’s population lives in places where air quality levels exceed WHO limits.
The PM10 concentration in Delhi’s air was found to be in the 225 microgram per millimetre square range.
Delhi’s pollution levels have been a cause of concern for some time, with the National Green Tribunal (NGT) stepping in and the state government adopting measures like restricting cars through the odd-even scheme. According to the pollution map, north India in general is in the very high pollution range.
Data derived from satellite measurements, air transport models and ground station monitors for more than 3,000 locations, both rural and urban, was used to compile the report. An estimated 3 million deaths a year are linked to exposure to outdoor air pollution. In 2012, an estimated 6.5 million deaths — 11.6 per cent of all global deaths — were linked to indoor and outdoor air pollution.
Nearly 90 per cent of air-pollution-related deaths occur in low- and middle-income countries, with nearly two out of three occurring in WHO’s South-East Asia and Western Pacific regions.
Among diseases linked to air pollution are cardiovascular diseases, stroke, chronic obstructive pulmonary disease and lung cancer. Air pollution also increases the risks for acute respiratory infections.
Major sources of air pollution include inefficient modes of transport, household fuel and waste burning, coal-fired power plants, and industrial activities, the report said. However, not all air pollution originates from human activities. For example, air quality can also be influenced by dust storms, particularly in regions close to deserts.