Section 40(19)(c) in The Punjab Liquor Licence Rules, 1956
(c)The licensee before selling any denatured spirits by retail shall use all reasonable diligence to ascertain the quantity already in purchaser's possession and shall not at one time sell to him more than one gallon, or such smaller quantity as, together with what is or in, good faith is believed to be in the buyer's possession, will amount to one gallon.