If the central government hadn't implemented measures to control the emissions of airborne pollutants between 2006 and 2010, this year's smog and acid rain could have been even more severe, according to an environmental report.

In a report the Chinese Academy for Environmental Planning released on Tuesday, sulfur dioxide emissions would have increased by 35 percent if not for the emissions control policy the government implemented during those five years.

Without the government's measures, twice the amount of sulfur would have settled on the ground, greatly increasing the frequency of acid rain. The report said if not for the policy, the number of cities not meeting national air quality standards would be 282 instead of the current mark of 264.

About 12.4 million metric tons of sulfur dioxide emissions were reduced from 2006 to 2010 when the country's gross domestic product grew from 18.49 trillion yuan ($3.03 trillion) to 40.15 trillion yuan, the report said.

Current levels of airborne pollution does not mean that past efforts made by all levels of government were ineffective, said Wu Shunze, deputy director of the academy. Wu said about 70 percent of the efforts to reduce emissions between 2006 and 2010 was intended to cut down on emissions generated during that period of time. During those five years, the country's coal consumption grew from 2.36 billion tons to 3.25 billion tons.

Controlling newly generated pollutants while maintaining emissions reductions is the biggest obstacle that the central government faces, Wu said.