Millions of Indonesians risk health complications from exposure to thick haze covering several cities and towns, officials said on Wednesday, as El Niño-fuelled wildfires wreak havoc on Borneo and Sumatra islands.Indonesia, a vast archipelago, has battled wildfires for weeks that have led to school closures and thousands of people requiring medical treatment, with smoke also reaching neighbouring Malaysia and Singapore.The health ministry said 3.4 million people living in seven provinces on Borneo and Sumatra were at risk of respiratory infections due to exposure.In Pekanbaru, the capital of Sumatra’s Riau province, thick smog forced the government to shutter dozens of schools as it urged residents to stay indoors.”The smog gets thicker at night, making Pekanbaru almost like a dead city. A lot of people don’t dare go out. And if they do, they wear masks,” Abdullah, a 38-year-old entrepreneur, told the AFP news agency.”My eyes sting so badly. When I go outside, it really feels like breathing in the smoke from freshly burned trash,” added the Pekanbaru resident who, like many Indonesians, has one name.In Jambi, also on Sumatra, 31-year-old homemaker Farida said the haze had already affected her family’s health.”My four-year-old child and I have begun coughing so much, especially when we stay outdoors too long,” she told AFP. “I have trouble breathing.”The Jambi local government has ordered home schooling for children in kindergarten and elementary school for the remainder of the week.The health ministry said it had distributed more than 260,000 face masks to residents of the hardest-hit areas.On Tuesday, President Prabowo Subianto said the government had deployed dozens of helicopters, aircraft, water pumps and thousands of personnel to battle the blazes.”Now I think it has begun to be brought under control, mitigated. In several places, I believe, and I hope that within the next one to two weeks everything can be resolved,” Prabowo said.Most wildfires are blamed on slash-and-burn practices to clear land for farming.Police said over the weekend they had arrested 72 people on suspicion of starting fires.Fires between January and July burned more than 200,000 hectares of land, an area three times the size of the capital Jakarta, the government said last week.That is already larger than during previous El Niño seasons in 2019 and 2023.The El Niño weather pattern triggers worldwide changes in winds, atmospheric pressure and rainfall.Malaysia said it stood ready to help put out fires.Poor air quality in Malaysia’s Sarawak state, on Borneo island which it shares with Indonesia and Brunei, led to nearly 600 schools being closed last week.At one point on Wednesday morning, tracker IQ Air ranked the Malaysian capital Kuala Lumpur second-most polluted city globally.