. This area now comprises the following regions in the western part of Tamil Nadu: Coimbatore , Gobichettipalayam , Pollachi , Tirupur , Erode , Nilgiris , Udumalaipettai , Avinashi , Perundurai , Bhavani , Komarapalayam , Sathyamangalam , Thiruchengode , Namakkal , Rasipuram , Karur , Kallakurichi , Palani ,