HOHHOT, May 11 (Xinhua) -- Authorities in north China's Inner Mongolia Autonomous Region are combating a rat plague by using various methods, according to the regional department of agriculture and animal husbandry Friday.

The rat plague has threatened around 4 million hectares of grasslands in the region since March, affecting the work and life of farmers and herdsmen as well as the sustainable development of animal husbandry.

In some areas, rats have ravaged the grasslands, eating grassroots and damaging prairies with underground digging.

The central government has allocated a 12 million yuan (1.9 million U.S. dollars) subsidy for local rat plague control.

More than 40,000 people have participated in the fight against rats, using methods such as poison sprays, hunting and biological control, which involves using natural predators to reduce the rat population.

The recent persistent drought is to blame for the rat plague, as rats are more adaptable to dry weather.