On the issue of any country blockading China's sea trade from the Indian Ocean and then to the Pacific and China...and blockading the Chinese made goods that flow back into the Indian Ocean and to all other oceans and seas...
I think that would have such adverse knock-on effects to world trade generally that no country would use such a blockade strategy.
China's sea trade is critically important to World economic health, particularly China's major trading partners which happen to include the USA,
South American countries, most European countries and most countries in Asia.
That includes India itself, Japan, the Koreas, Taiwan, Southeast Asia and Australia as well as most major economies I haven't mentioned.
Also OPEC values China's demand for oil highly. An unhappy OPEC, especially Saudi Arabia, would also have adverse international trade and financial impacts.
In this intensively globalised world curtailing China's trade would rapidly impact, even close, stock exchanges, currency markets, metals and primary products markets, US debt bonds and every other economic balance.
China has a very large economy - so it cannot be marginalized like much smaller economies, for example:
- Japan's economy prior to 1941 and even that led to the Pacific War
- the Soviet Union's comparitively small economy during the Cold War, or
- the Soviet Union's comparitively small economy during the Cold War, or
- Russia's comparitively small economy today (which is one tenth of China's).
Take out China's goods servicing the international supply chain and you take out world trade.
Take out China's goods servicing the international supply chain and you take out world trade.
Blockading China's trade is not a viable naval tactic, given the high costs to everyone.