BANGALORE, India -- Top Indian scientists Monday slammed a UN-backed study on the "Asian brown cloud" phenomenon, describing it as "exaggerated and distorted" and said Asia was not the only source of pollution.

"The study has made sensational statements on the impact of pollution on monsoons and agriculture which are exaggerated and distorted," J. Srinivasan, chairman of center for atmospheric and oceanic sciences said.

"It has come to conclusions without any scientific basis," he said.

In August the United Nations Environment Program (UNEP) said the "Asian brown cloud" -- a vast haze of pollution stretching across South Asia -- was damaging agriculture, modifying rainfall patterns and endangering the population.

UNEP said the pollution caused by the burning of agricultural wastes and fossil fuels, and inefficient cooker emissions from burning wood, cow dung and other bio-fuels.

Srinivasan said the term "Asian brown cloud" was misleading and the scientists were worried about the implications that were suggested in the report, AFP reported.

"Actually it is a haze that we see. Perhaps the name 'Asian brown cloud' was chosen to give an impression of the Asian region choking under a thick and permanent blanket of dirty atmosphere," he told reporters here.

He said the haze was not a permanent feature in the Asian region and occurred only between January and March -- the period in which the UN body conducted the study said.

"The haze disappears during the ensuing monsoon season and even during January-March there is considerable variation from year-to-year in the intensity of the haze," he said.

"It appears that the term 'Asian brown cloud' for describing wintertime haze over the Asian region is not appropriate and the implicit suggestion that it is a feature that characterizes only the Asian region is incorrect," he said.

"The scourge of pollution is by no means restricted to the Asian region. Man-made aerosol pollutants (sulphate or soot) are rampant in Europe and the United States. A lot of blame is laid at our door," Srinivasan said.

"The attitude of the scientists as reflected in the study involves blaming the developing countries in Asia for the pollution of the planet.

"Rather than advocating international agreements to control pollution the attitude seems to be one of imposing an asymmetric control regime," he said.

The UN-backed study quoting global models suggested that the blanket may reduce precipitation over northwest India, Pakistan, Afghanistan, Western China and the western part of Central Asia by between 20 and 40 percent.

It said a 10-percent reduction in the amount of solar energy hitting the region's oceans in turn reduces the evaporation of the moisture which controls summer rainfall.

This may already be having significant impacts on agriculture and the study said that the haze may be reducing India's winter rice harvests by as much as 10 percent.

Sulochana Gadgil, professor at the Center for Atmospheric and Oceanic Studies said the reliability of the model used by UNEP was in question.

"The study has pointed out a decrease in rainfall over Pakistan and Afghanistan due to the pollution.

"But the model stimulation of the rainfall patterns over the region, where the haze is supposed to lead to a decrease in rainfall, is particularly poor and hence reliability of this projection is a suspect," Gadgil said.

Klaus Toepfer, UNEP chief, said last month more research was needed on the topic.

"More research is needed, but these initial findings clearly indicate that this growing cocktail of soot, particles, aerosols and other pollutants are becoming a major environmental hazard for Asia," he had said.