As an observation: it should be noted that the majority of the world's shipping use the Straits....hence any action there will involve more than India and China...
Hi, don't forget
Yarlung Zangbo River. If China build a dam on the river, that's the most horrible for India. Imagine it, when spring China store water in the dam, when summer China let the water out.
In addition, China can benefit from the huge water power from the dam.