Section 1A(1)(j) in The Merchant Shipping (Control of Pollution by Noxious Liquid Substances in Bulk) Rules, 2010
(j)"En route" means that the ship is under way at sea on a course or courses, including deviation from the shortest direct route, which as far as practicable for navigational purposes, shall cause any discharge to be spread over as great an area of the sea as reasonable and practicable;