NORTH WESTERN PLAINS ZONE (NWPZ) Punjab, Haryana, Delhi, Rajasthan (except Kota and Udaipur divisions) and Western UP (except Jhansi division), parts of J&K (Jammu and Kathua distt.) and parts of HP (Una dist. and Paonta valley) and Uttaranchal (Tarai region)
NORTH EASTERN PLAINS ZONE (NEPZ) Eastern UP, Bihar, Jharkhand, Orissa, West Bengal, Assam and plains of NE States
CENTRAL ZONE (CZ) Madhya Pradesh, Chhattisgarh, Gujarat, Kota and Udaipur divisions of Rajasthan and Jhansi division of Uttar Pradesh
PENINSULAR ZONE (PZ) Maharashtra, Karnataka, Andhra Pradesh, Goa, plains of Tamil Nadu