Quick answer: A chain rusts when bare metal meets water. Rain washes off the lube, India's humidity keeps the metal wet, and an unlubed chain has no protection. Stop it by keeping the chain clean, dry and lubed — chain lube seals out moisture, and a rust remover handles rust that's already started.

The 3 causes

1. No lube — bare metal is unprotected.
2. Water — rain and puddles wash lube away.
3. Humidity — keeps the metal wet long enough to rust.

How to stop it

Clean with a chain cleaner, dry, and lube every 500 km and after wet rides. Already rusty? See how to clean a rusty chain.

FAQ

Does lube really prevent rust? Yes — it seals the metal from moisture. A dry chain is the #1 cause of rust.