Police in Madhya Pradesh'sRatlam on Sunday booked two persons under the stringent National Security Act (NSA) for assaulting a police sub- inspector while he was enforcing coronavirus-induced lockdown in a containment zone in the city, a senior officer said.A group of 20 people had attacked the sub-inspector Jairam Jamod on Friday night, district superintendent of police (SP) Gaurav Tiwari said."Jamod had received information that some people had started gathering at a crossing in Mochipur containment area. He rushed to the spot and made an announcement on a speaker phone asking people to stay indoors when he was attacked. A volunteer, identified as Suhail who tried to save the SI, was also beaten up," he said.Police have registered a case against 20 people and arrested 11 of them, the SP said, adding that two of them were booked under the NSA.A video clip of the assault had gone viral on social media.