Lets discuss a bit, China's problems with India.
1.
Northern Land Borders: Only India and Bhutan have unsettled borders with China in the North. They dont want to settle the land borders, so that India stays distracted in the mountains and not focus on the Indian Ocean region, where lies major vulnerability for the Chinese.
2.
China's Indian Ocean vulnerability Most are aware of the Malacca strait choke point, from where China's shipping lanes can be choked, all export/import of goods mostly comes to a stop, if that were to be blocked.
However, there are other choke points.
a) As you come out of the Malacca straits, Chinese ships have to pass to the south of the Andaman Nicobar islands (which belong to India). Its a major naval base (Andaman Nicobar command). So called 10 degree channel.
b) Recently, Maldives (muslim state on the south west of Sri Lanka)), tried to kick out India and replace them with China, forgetting that they are completely reliable on India for their economy, tourists and even fresh water!. No doubt a lot of money exchanged hands after their new President was elected. China thought they gained a major foothold in the Indian Ocean (no base as yet). Problem is that India activated a new naval base in the Minicoy islands (India owned) between Minicoy and Maldives, the so called 8 degree channel. this creates a new choke point.
c) Further north of Minicoy are major naval bases in the Lakshdweep islands (India owned), so called 9 degree channel, which is another choke point.
d) Look south of the Maldives, there lies Diego Garcia a part of the Chagos Islands, a major US base.
e) Even if Chinese subs were to cross south of these choke points, India has additional listening stations in Madagascar, Seychelles, Mauritius etc, These islands have many Indian origin people due to historical trade routes and relations are very close with India.
China is in no position to exert force in the Indian Ocean, unless they are dealing with small nations such as Phillipines, Vietnam etc.