places nearby chennai city call themselves chennai will not have chennai pin code and cmda approvals. thus proves those regions were outside chennai. chennai city pin code starts with chennai city 600001 to 600130. rest pin codes were not considered as chennai like starts with 601, 602 or 603 etc.there are some exceptions, still thirunindravur has the pincode 602024 and it's part of chennai city. due to slow growth in development and since this pincode serves a larger area the pincode hasn't been changed yet to this location. there are few other places in south chennai has pincode starts with 602 and 603 and still considered as part of chennai.