Varanasi, May 9 -- Security of Rihand and Obra dams has been tightened, and monitoring of power plants has been increased, said a senior police officer. Surveillance has also been increased at Obra, Anpara, and NTPC's Rihand, Singrauli, and Vindhyachal thermal power units. District police and CISF personnel have been instructed to maintain a strict vigil, the officer added. Additional superintendent of police, Sonbhadra Headquarters, Kalu Singh, said that security has been beefed up at industrial projects and thermal power plants in the district. Monitoring of security arrangements is underway. Rihand Dam and Obra Dam are sources of water for power generation and are strategically important. Pipri circle officer Amit Kumar and station officer Nagesh Singh visited Rihand Dam and discussed security measures with the CISF deputy commandant. Rihand Hydroelectric Power Station's executive engineer, Shashikant Rai, confirmed the visit and said surveillance has been increased and security has been heightened. htc...