WHO reported that India is home to four of the five cities in the world with worst air pollution.
2 most polluted cities out of top 5: 
- Gwalior – 2nd
- Allahabad – 3rd
Other Two Indian Cities:
- Patna – 6th
- Raipur – 7th
The dirtiest air was recorded at Zabol in Iran
WHO experts reported that India faces a “huge challenge”, many countries are so bad that they have no monitoring system and cannot be included in its ranking.
Delhi ranks 11th
- Measured by the amount of particulate matter (PM) under 2.5 micrograms found in every cubic metre of air, with an annual average PM 2.5 measurement of 122.
- Due to toxic air by limiting the use of private cars on the road for short periods
Tiny particulate matter can cause
- i. Lung cancer
- ii. Strokes
- iii. Heart disease
The WHO stated that more than 7 million premature deaths occur every year due to air pollution, 3 million of them due to outdoor air quality.
80 per cent of world’s city dwellers breathing bad air: United Nations reported
Causes of air pollution:
- Diesel-fuelled vehicles
- Heating and cooling of big buildings
- Waste management
- Agriculture and the use of coal or diesel generators for power
About WHO:
Specialized agency of the United Nations that is concerned with international public health
- Headquarters: Geneva, Switzerland
- Founded: April 7, 1948
- Head: Margaret Chan