Any feature of IRI must given equally to all cities. You are still thinking of old classification of Tier-I cities (4 cities). Now there is good development in other major cities. Hence Tier-I cities have been increased from 4 to 9 by Government of India. Current Tier-I cities are Delhi, Mumbai, Kolkata, Chennai, Bengaluru, Hyderabad, Ahmedabad, Pune and Kochi