Outdoor air pollution worldwide has increased by eight percent in the past five years, according to the new data released by World Health Organisation (WHO).
Based on the data gathered by WHO, billions of people around the world are now exposed to dangerous air and more than 3,000 cities are compiled and reported as polluted.
The most affected of the air pollution increase are the poor countries and the fast-growing cities in the Middle East, south-east Asia and the western Pacific, the Guardian reports.
The new WHO database, which has been released recently, shows that levels of ultra-fine particles of less than 2.5 microns (PM2.5s) are highest in India. This country has 16 of the world's 30 most polluted cities. The poorest cities often deal with the air quality standards, according to a report released Thursday by WHO.
China has been plagued by air pollution but luckily, the country has improved its air quality since 2011. Nine other countries, including Pakistan and Iran, have one city each included in the list of top 30 worst and polluted cities.
Meanwhile, Huffington Post listed top 10 cities with that contributed air pollutants in the planet. In the list, the worst air polluted cities include Zabol, Iran, Gwalior, India, Allahabad, India, Riyadh, Saudi Arabia, Jubail, Saudi Arabia, Patna, India, Raipur, India, Bamenda, Cameroon, and Xingtai, China.
The organization's study measured the levels of deadly particles suspended in the atmosphere. They found out that 98% of cities in low and middle income countries failed to meet WHO air quality standards.
Zabol in Iran and Onitsha in Nigeria tied for being a worst city with polluted air, and India had 16 cities in the top 30 worst cities with air pollution. China has five cities included in the top 30.