If you're carrying more than one debt, you have two well-tested strategies for which to pay off first, and they optimise for different things: avalanche saves you the most money, snowball gives you the fastest emotional wins.
Here's how each works. Avalanche: pay the minimum on everything, then throw every spare rupee at whichever debt has the highest interest rate — say, a ₹40,000 credit card balance at 36% — until it's gone, then move to the next highest. This minimises the total interest you'll ever pay, full stop, mathematically the cheapest path. Snowball: pay the minimum on everything, then attack the smallest balance first — perhaps a ₹15,000 personal loan — regardless of its rate, clear it fast, and roll that payment into the next-smallest debt.
Why the "wrong" one sometimes wins in practice: avalanche is objectively cheaper, but it can take a long time before you see a debt fully disappear, which is discouraging for some people. Snowball costs a bit more in total interest but delivers an early win — a debt gone in two months — that builds real momentum to keep going.
The honest answer to "which should I use?" is whichever one you'll actually stick with for the next year. If you're disciplined and numbers-motivated, avalanche saves you more. If you need visible progress to stay engaged, snowball's quick wins might get you further in the end. Either beats the third option, which is no strategy at all.