Only Seven Countries Met WHO Air Quality Standards in 2024, Data Shows 

A general view shows the Signature Bridge over the Yamuna River on a smoggy winter morning in New Delhi on December 20, 2024. (AFP)
A general view shows the Signature Bridge over the Yamuna River on a smoggy winter morning in New Delhi on December 20, 2024. (AFP)
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Only Seven Countries Met WHO Air Quality Standards in 2024, Data Shows 

A general view shows the Signature Bridge over the Yamuna River on a smoggy winter morning in New Delhi on December 20, 2024. (AFP)
A general view shows the Signature Bridge over the Yamuna River on a smoggy winter morning in New Delhi on December 20, 2024. (AFP)

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 US 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 US government's official air quality monitoring site, airnow.gov, including readings collected in Chad.

"Most countries have a few other data sources, but it's going to impact Africa significantly, because oftentimes these are the only sources of publicly available real-time air quality monitoring data," said Christi Chester-Schroeder, IQAir's air quality science manager.

Data concerns meant Chad was excluded from IQAir's 2023 list, but it was also ranked the most polluted country in 2022, plagued by Sahara dust as well as uncontrolled crop burning.

Average concentrations of small, hazardous airborne particles known as PM2.5 hit 91.8 micrograms per cubic meter (mg/cu m) last year in the country, slightly higher than 2022.

The WHO recommends levels of no more than 5 mg/cu m, a standard met by only 17% of cities last year.

India, fifth in the smog rankings behind Chad, Bangladesh, Pakistan and the Democratic Republic of Congo, saw average PM2.5 fall 7% on the year to 50.6 mg/cu m.

But it accounted for 12 of the top 20 most polluted cities, with Byrnihat, in a heavily industrialized part of the country's northeast, in first place, registering an average PM2.5 level of 128 mg/cu m.

Climate change is playing an increasing role in driving up pollution, Chester-Schroeder warned, with higher temperatures causing fiercer and lengthier forest fires that swept through parts of South East Asia and South America.

Christa Hasenkopf, director of the Clean Air Program at the University of Chicago's Energy Policy Institute (EPIC), said at least 34 countries will lose access to reliable pollution data after the US program was closed.

The State Department scheme improved air quality in the cities where the monitors were placed, boosting life expectancy and even reducing hazard allowances for US diplomats, meaning that it paid for itself, Hasenkopf said.

"(It) is a giant blow to air quality efforts worldwide," she said.



New T-Rex Ancestor Discovered in Drawers of Mongolian Institute

A life reconstruction of the newly identified dinosaur species Khankhuuluu mongoliensis, which lived 86 million years ago in Mongolia, is seen in this handout illustration released on June 11, 2025. (Julius Csotonyi/Handout via Reuters)
A life reconstruction of the newly identified dinosaur species Khankhuuluu mongoliensis, which lived 86 million years ago in Mongolia, is seen in this handout illustration released on June 11, 2025. (Julius Csotonyi/Handout via Reuters)
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New T-Rex Ancestor Discovered in Drawers of Mongolian Institute

A life reconstruction of the newly identified dinosaur species Khankhuuluu mongoliensis, which lived 86 million years ago in Mongolia, is seen in this handout illustration released on June 11, 2025. (Julius Csotonyi/Handout via Reuters)
A life reconstruction of the newly identified dinosaur species Khankhuuluu mongoliensis, which lived 86 million years ago in Mongolia, is seen in this handout illustration released on June 11, 2025. (Julius Csotonyi/Handout via Reuters)

Misidentified bones that languished in the drawers of a Mongolian institute for 50 years belong to a new species of tyrannosaur that rewrites the family history of the mighty T-Rex, scientists said Wednesday.

This slender ancestor of the massive Tyrannosaurus Rex was around four meters (13 feet) long and weighed three quarters of a ton, according to a new study in the journal Nature.

"It would have been the size of a very large horse," study co-author Darla Zelenitsky of Canada's University of Calgary told AFP.

The fossils were first dug up in southeastern Mongolia in the early 1970s, but at the time were identified as belonging to a different tyrannosaur, Alectrosaurus.

For half a century, the fossils sat in the drawers at the Institute of Paleontology of the Mongolian Academy of Sciences in the capital Ulaanbaatar.

Then PhD student Jared Voris, who was on a trip to Mongolia, started looking through the drawers and noticed something was wrong, Zelenitsky said.

It turned out the fossils were well-preserved, partial skeletons of two different individuals of a completely new species.

"It is quite possible that discoveries like this are sitting in other museums that just have not been recognized," Zelenitsky added.

They named the new species Khankhuuluu mongoliensis, which roughly means the dragon prince of Mongolia because it is smaller than the "king" T-Rex.

Zelenitsky said the discovery "helped us clarify a lot about the family history of the tyrannosaur group because it was really messy previously".

The T-Rex represented the end of the family line.

It was the apex predator in North America until 66 million years ago, when an asteroid bigger than Mount Everest slammed into the Gulf of Mexico.

Three quarters of life on Earth was wiped out, including all the dinosaurs that did not evolve into birds.

Around 20 million years earlier, Khankhuuluu -- or another closely related family member -- is now believed to have migrated from Asia to North America using the land bridge that once connected Siberia and Alaska.

This led to tyrannosaurs evolving across North America.

Then one of these species is thought to have crossed back over to Asia, where two tyrannosaur subgroups emerged.

One was much smaller, weighing under a ton, and was nicknamed Pinocchio rex for its long snout.

The other subgroup was huge and included behemoths like the Tarbosaurus, which was only a little smaller than the T-rex.

One of the gigantic dinosaurs then left Asia again for North America, eventually giving rise to the T-Rex, which dominated for just two million years until the asteroid struck.