30-year-old Madvi Mangu was among the two rebels captured after a gun battle in a forested area of Bijapur, 450 km away from Raipur.
"The tribal militant had excess bleeding and was in desperate need of B-positive blood. Doctors said he would die if blood was not arranged urgently on Sunday," Superintendent of Police P. Sundarraj said.
"Two constables, Chaganlal Daharia and Hari Singh Thakur posted at Jagdalpur town, immediately agreed to donate blood and finally saved his life. Now doctors say the militant is out of danger," the police officer said.
Daharia said, "It was a decision linked to someone's life and I had to take it in a flash though he belonged to an insurgent group that has massacred so many of our colleagues in the past several years. But I thought I should not inherit their culture based on brutality and inhumanity and donated blood."
Mangu is recovering well but authorities plan to send him to Raipur for advanced treatment. The rebel thanked the policemen who donated blood and promised to work for peace in Bastar region, said the police.