Mönkhbayar was elected to chair the local citizens' council in the Ongi River region 1996, after actively participating in meetings for some time.
Illegal mining practises and weak law enforcement resulted in contamination and depletion of the river.
With the Ongi River Movement, Mönkhbayar convinced the Mongolian Government and Parliament to pass and enforce more restrictive laws in 2006.
This has led to a significant improvement of the quality and amount of water in the river.
Later he was sentenced to 7 years in prison for attempting to enter a protected area of the Government House with a firearm and open fire.