Data from China Association of Automobile Manufacturers (CAAM) showed that auto sales in China fell for a 17th consecutive month in November, with the number of new energy vehicles (NEVs) sold contracting for a fifth month in a row.

Total auto sales in the world’s biggest auto market fell 3.6% from the same month a year earlier. That follows a drop of 4% in October and 5.2% in September. Car sales in the country contracted last year for the first time since the 1990s against a backdrop of slowing economic growth and a crippling Sino-U.S. trade war.

“The China 5-6 emission standard change is the biggest reason for this year’s sales plunge,” said Chen Shihua, deputy secretary general at CAAM, referring to how local governments had accelerated changes to emission standards this year.

He added that overall car production levels were now returning to normal and carmakers had boosted their product line-ups in the past few months.

In November, sales of NEVs fell 43.7%, CAAM said, following a 45.6% drop in October. NEV sales had jumped almost 62% last year even as the broader auto market contracted.