On 12 May 2016 The World Health Organisation (WHO) in a survey announced that New Delhi is no longer the worst polluted city in the world in terms of air quality. However, India is home to four of the five cities in the world with the worst air pollution.
• The dirtiest air was recorded at Zabol in Iran, which suffers from months of dust storms in the summer. Zabol clocked PM2.5 measure of 217.
• The next four cities in the list were Gwalior, Allahabad, Patna and Raipur.
• New Delhi was the survey's 11th worst city, measured by the amount of particulate matter under 2.5 micrograms found in every cubic metre of air. Delhi had an annual average PM2.5 measurement of 122.
• Populations in low-income cities are the most impacted.
• 98% of cities in low- and middle income countries with more than 100000 inhabitants do not meet WHO air quality guidelines.