Haven’t flown 6E in a while but I fly AI very regularly domestically.

Most of their flights are really full these days, especially during business flight times on key routes. For Economy, they may not check weight as much as force you to gate check your bag because of space constraints.

If you’re in PE or J (J gives you a 10kg weight limit) you won’t be asked to gate check. In my experience at BOM or DEL, they generally never ask you to weigh your bag at check-in. At CCU, MAA, BLR, IXC and HYD, I have been occasionally asked to weigh my main cabin bag (not my backpack) to ensure it was below 10kg.