Indonesia’s capital will force drivers to undergo emission tests, officials said on Monday, amid deteriorating air quality that has made Jakarta one of the world’s most polluted cities.

Jakarta has been consistently ranked among the 10 most polluted cities globally since May and last week topped global rankings compiled by Swiss air quality technology company IQAir. On Monday, Jakarta ranked second.

During a cabinet meeting on Monday, Indonesian President Joko Widodo blamed the problem largely on “excessive road traffic, a long dry season, and manufacturing industry mainly those using coal.”

The president himself has been struggling to shake off a cough for nearly four weeks, which one official blamed on the high levels of pollution in Jakarta.

“Possibly, as the president’s doctor said, the sickness is contributed by unhealthy and poor quality of air,”

Tourism minister Sandiaga Uno said after the cabinet meeting.

Environmental groups have long pointed to coal-fired power plants as the cause of high pollution.

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The government said it would carry out random checks on vehicles and force drivers to undergo emission tests. It will consider fines for those who fail and license revocation for repeat offenders.

The Jakarta city government was also considering ordering half of its civil servants to work from home.

The central government will also require emission tests to be part of the process of obtaining a vehicle registration license in the capital city. It did not say when the measures would be introduced or how they would be enforced.

“We will start in Jakarta and when it gets better, we will expand it to greater Jakarta,”

Environment minister Siti Nurbaya Bakar told a press conference.

President Widodo also advised companies to impose hybrid working and urged weather modification in Greater Jakarta, saying dry weather was contributing to pollution. Weather modification includes techniques such as cloud seeding, already used in Indonesia during the dry season, which involves shooting salt flares into clouds to trigger rainfall.

“Also, keep monitoring the industrial sector and power plants mainly surrounding Greater Jakarta,” he told ministers.

Other measures under consideration include requiring cars with 2,400 cc engine capacity and above to use 98-octane fuel, and requiring each vehicle to carry four people.

Jakarta residents, which number well over 10 million, have long complained of poor air.

A group of residents won a landmark civil case against the government in 2021, prompting President Widodo to order the establishment of national air quality standards to protect human health and to tell the health minister and Jakarta governor to devise strategies to control air pollution.