THIRUVANANTHAPURAM: In the wake of heavy rain lashing the state, the Government has sought the help of the National Disaster Response Force (NDRF) as a precautionary measure. Three companies of NDRF personnel will be deployed in Idukki, Ernakulam and Kozhikode districts. All District Collectors have been asked to be on alert. RevenueMinister Adoor Prakash said control rooms would be opened at taluk-level if the need arises.