Section 99(i) in Kerala Survey and Boundaries Rules, 1964
(i)The blocks into which the town has been divided during survey will be classified as 'close', 'medium' and 'open' according to the number of houses in them. An acre/40 Ares of close area shall be considered as equivalent to 4 acres/160 areas of medium and 12 acres/480 Ares open area .
