The planned introduction of a stricter national emission standard for all new heavy-duty vehicles will proceed as scheduled from July 1, and will prohibit the production, import and sales of vehicles that do not meet the standard, according to the latest guideline.

The standard, known as China VI-b, will help reduce air pollution and contribute to environmental protection, and it is also expected to promote the healthy development of the domestic car market, industry players observed.

When the new guideline is implemented, all new heavy-duty vehicles sold in the country are required to meet the standard as the government aims to help stabilize and expand automobile consumption in the country, according to a statement released by the Ministry of Industry and Information Technology and four other departments on Tuesday.

Emissions from cars have become a significant source of air pollution in large and medium-sized cities in China, and the urgency of strengthening the control of such pollution has become increasingly prominent. In 2021, total emissions of four pollutants from motor vehicles nationwide exceeded 15.5 million metric tons, according to the Ministry of Ecology and Environment.

Revealed in 2018, the China VI standard is made up of two sub-standards — China VI-a and China VI-b. The overall standard combines practices from both European and United States regulatory requirements, in addition to creating its own.

China VI-a is largely equivalent to Euro VI, and China VI-b introduces slightly more stringent testing requirements and a remote emission monitoring system, according to the International Council on Clean Transportation.

The China VI-a took effect nationally on July 1, 2020, and many regions had even adopted it a year earlier.

The stricter China VI-b had been scheduled for July 1 this year, although some industry players called for postponing this date in recent months. Tuesday's release of the guideline has reassured them, observers said.

"The policy is expected to play a significant role in helping stabilize the development of the car market by stabilizing the mentality of car dealers, manufacturers and the pace of production and sales," said Cui Dongshu, secretary-general of the China Passenger Car Association.

Specifically, the China VI-b standard features reductions in nitrogen oxides and particulate matter emission limits by around 70 percent from the previous China V standard, and it has extended durability requirements.

Meanwhile, the guideline noted that for light-duty commercial vehicles, if their pollutant emission testing reports from actual driving showed a result that only requires monitoring, a six-month sales transition period will be granted and such vehicles will be allowed for sale until Dec 31.

Li Fusheng contributed to this story.