By DAVID STANWAY Reuters
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SINGAPORE — Only seven countries met World Health Organization (WHO) air quality standards last year, data showed on Tuesday, as researchers warned that the war on smog would only get harder after the United States shut down its global monitoring efforts.

Chad and Bangladesh were the world’s most polluted countries in 2024, with average smog levels more than 15 times higher than WHO guidelines, according to figures compiled by Swiss air quality monitoring firm IQAir.

Only Australia, New Zealand, the Bahamas, Barbados, Grenada, Estonia and Iceland made the grade, IQAir said.

Significant data gaps, especially in Asia and Africa, cloud the worldwide picture, and many developing countries have relied on air quality sensors mounted on U.S. embassy and consulate buildings to track their smog levels.

However, the State Department has recently ended the scheme, citing budget constraints, with more than 17 years of data removed last week from the U.S. government’s official air quality monitoring site, airnow.gov, including readings collected in Chad.