Asian Tech Press (May 26) -- Chinese EV maker BYD was accused by rival Great Wall Motors (GWM) of not meeting emissions standards on Thursday, which sparked a buzz on Chinese social media platforms.

In a post on its official Weibo account on Thursday morning, GWM said it had submitted a complaint about BYD to Chinese regulators on April 11.

In the statement, GWM said that the BYD Qin PLUS DM-i and Song PLUS DM-i, two of BYD's best-selling new energy vehicles, use atmospheric fuel tanks and are suspected to not meet evaporative emission standards for the complete vehicle.

Less than two hours later, BYD issued a statement in response on its official Weibo account, saying it "firmly opposes any form of unfair competition."

BYD said that the test vehicles were purchased, stored and arranged to be sent for inspection by GWM, which does not meet the national standard requirements for a car inspection.

"In light of the above, BYD believes that its test report is invalid and cannot be used by GWM as a basis," BYD stressed.

BYD also said that its products and related tests comply with national standards and are certified by national authorities.

BYD and GWM both dropped in Hong Kong stock market on Thursday due to the whistle-blowing incident. By the closing bell of the day, the two companies were down more than 5% and 7% respectively.

BYD, the largest electric car manufacturer in China, is considered to be the most likely of the Chinese companies to become second only to Tesla, the world's largest EV maker.

Despite rising sales, BYD has been facing more pressure in addition to the accusations from its Chinese rival.

On May 2, billionaire Warren Buffett's investment firm Berkshire Hathaway Inc. sold 1.961 million BYD shares, cashing out at HK$462.1 million (US$58.9 million), a Hong Kong Stock Exchange filing disclosed.

This is at least the 11th time Buffett has reduced his holdings in BYD since August last year, dropping from 19.92% at the time to 9.87%, a reduction of more than half.

Some industry analysts said that from Buffett's investment habits, winding down his holdings in BYD should be a high probability event.

In addition, BYD's Changsha plant was also caught in a furore at the end of April when employees left en masse, the automaker allegedly limiting the number of departures.

However, it denied claims that the number of departures was full and that there had been "mass resignations".