I think in a lot of the situations, there's a simple rule that Indian drivers follow, which is like motor boats official rules: the biggest vehicle has priority.

So when it comes to u-turns, cars won't do a u-turn if there's a van or bus coming from the other side, but a bus will have no problem starting a u-turn if there's only a flow of cars and motorcycles coming.

Motorcycles are just expected to flow around, make their u-turn small and fast.

Same thing when it comes to overtaking on small roads, or when there's those traffic police barricades at the entry/exit of towns, which reduces the road size to only one way. At those barricades, people will rarely have to come to a complete stop: they just look at how big the vehicle in front of them is, and if it's bigger they'll slow down to give it priority.

For overtaking, in Western countries we'd just consider whether there's enough space/time to safely overtake (unless you're a driver from the mountain regions), but in India they also consider who would win if there was a frontal crash, and the would-be loser will slow down if needed to make sure the bigger vehicle on the other side can finish overtaking.

The equivalent of the sailing boat in term of priority are the cows on the road: they get priority over any motor vehicle