BEIJING, Nov. 18 (Xinhua) -- Several data revealed by a global research endeavor showed that the Tibetan plateau remains one of the world's cleanest regions despite pollutants discharged by surrounding regions.

"The environment background value of pollutants in the Tibetan plateau, which is similar to that of the Arctic, is remarkably lower than that of densely-populated areas," said an environment change evaluation report organized by the Institute of Tibetan Plateau Research of the Chinese Academy of Sciences (CAS).

Pollutants in the air of the plateau, such as black carbon and heavy metal, have increased by two times since the 1950s, the report said.

Citing lake and ice core records, the report said South Asia and Central Asia are the two major contributors to the plateau's black carbon, a climate forcing agent which heats atmosphere and warms the Earth.

The average deposition of black carbon in southeastern and central parts of the plateau from the beginning of this century was three times the average in the period between the 1950s and the 1980s.

"Black carbon on the plateau is now at its highest level in nearly 100 years, which is lower than that in the Alps in France and similar to the Arctic," the report said.

Though the level of heavy metal recorded in ice and lake cores of the plateau is higher than or similar to the south and north pole regions, it is much lower than that in densely-populated areas.

In addition, persistent organic pollutants (POPs) in the air remain at a relatively low level, which is close to or lower than that in the Arctic region or the Alps.

The plateau's disaster risks increase as climate is warming and human activities are increasing.

If humans continue to exert a positive influence on environment and improve disaster early warning capability, the low environment background value as one of the world's cleanest areas could be maintained, the report said.

The CAS institute describes the Tibetan plateau in its report as the areas mainly in southwest China's Tibet Autonomous Region, with an average altitude of over 4,500 meters.