Section 46(1)(c) in The Static and Mobile Pressure Vessels (Unfired) Rules, 2016
(c)the surrounding area lying within 100 metres from the edge of all facilities which are proposed to be licensed; however, for major installations of flammable or toxic gases including LNG exceeding total capacity of product 50 metric tons or 100 m3 water capacity of each vessel, whichever is less, area lying within 500 metres along with Hazard and Operability (HAZOP) study and a risk analysis report prepared by a reputed agency;