While states like Assam, Nagaland, Manipur, Tripura and Arunachal Pradesh registered declining figures of insurgency related violence, the law and order situation has deteriorated in Meghalaya, said Pillai.
He was in Guwahati to participate in a seminar on 'Sustaining Peace in Northeast India: Changing Dimensions' organised by the Centre for Development and Peace Studies.
In Assam, violent incidents had come down to 145 in 2011 compared to 251 in 2010, and only 46 extremists were killed last year against 109 in 2010. Similarly, he said, support base of militants was also decreasing after various factions surrendered and took part in the democratic process by contesting elections.
"In Nagaland, there were only 61 incidents of violence in 2011 compared to 64 in 2010. No security personnel have been killed in last several years in Nagaland," Pillai, who is a distinguished fellow of the Institute for Defence Studies and Analyses (IDSA), added.
"The situation is seemingly improving in Manipur, perhaps the most problematic state in the northeast. The number of incidents has come down to 298 in 2011 compared to 367 in 2010...."
However, the number of security personnel killed has increased to 10 in 2011 compared to six in 2010, he said, probably because no genuine dialogue has taken place so far with the militant groups in Manipur. He also said that the state police force had become politicised and highly dysfunctional.
"Arunachal Pradesh is by and large peaceful except the two districts of Tirap and Changlang."
The situation in Tripura is also improving as only 13 incidents occurred in 2011 as compared to 30 in 2010, Pillai said.
But Meghalaya tells a different story.
"However, the law and order has been deteriorating in Meghalaya in the last few years. A total of 56 incidents took place in Meghalaya in 2011 compared to 29 in 2010," the retired bureaucrat said, adding that the growing tribal rivalry and political uncertainties had resulted in the lack of attention to governance and security matters.
"Mizoram and Sikkim are beacons of peace and other states of the region must learn from their examples," said Pillai.