Section 2(u) in The Petroleum And Natural Gas Regulatory Board Act, 2006
(u)"liquefied petroleum gas" means a mixture of light hydrocarbons containing, propane, isobutane, normal butane, butylenes, or such other substance which is gaseous at normal ambient temperature and atmospheric pressure but may be condensed to liquid state at normal ambient temperature by the application of pressure and conforms to such specifications, as the Central Government may, in consultation with the Bureau of Indian Standards, notify from time to time;
