SHENZHEN (BLOOMBERG) - BYD, the Chinese automaker backed by Warren Buffett, has come under fire for pollution at one of its factories that residents say has caused nosebleeds in hundreds of children.

Officials in Changsha, the capital of central China's Hunan province, sent a team to BYD's factory to investigate gas emissions after receiving complaints from neighbours, the local government said in a statement on its official Weibo account on Sunday (May 8).

The team includes third-party testing institutions and experts who'll try to get to the bottom of the issue that's seen scores of parents in Changsha protest. According to one report, more than 600 children living near the production plant in the city's Yuhua district have experienced repeated nosebleeds since April.

Shenzhen-based BYD said over the weekend that its emissions comply with regulations and noted it has taken steps to reduce the odour caused by the plant, which has been in operation since 2012.

BYD also said that it has filed police reports alleging the complaints about nosebleeds are groundless and malicious.

The company's China-traded shares dropped on Monday, falling as much as 4.6 per cent, their biggest intraday decline in almost two weeks. Markets in Hong Kong, where BYD is also listed, are closed for a public holiday.

BYD is one of China's most successful car companies in terms of sales, producing both conventional gas automobiles as well as electric vehicles. It also makes batteries for EVs.