Step 1: Picture India's map with the two coasts.
West coast (Arabian Sea): Mumbai, Kandla, Kochi, Mangalore, Marmagao. East coast (Bay of Bengal): Chennai, Vishakhapatnam, Paradip, Kolkata.
Step 2: Spot the odd one out.
Three of the four options belong to the west-coast list; Chennai belongs to the east-coast list instead.
Final Answer:
So option (c) Chennai is the one not on the western coast.$\boxed{\text{Chennai}}$