The 46 billion dollars that China will invest in the China-Pakistan Economic Corridor include the investment for the Chinese naval base in the Pakistani port of Gwadar at the Indian Ocean. The Chinese naval bases in the Indian Ocean will make China a two ocean super power, and will allow her together with her ally Pakistan to encircle India.
India on the other hand is trying to respond by encircling China with her defense cooperation with Vietnam, Indonesia, Australia, Japan and South Korea.
Map 1 India VS China
India also has the advantage that she has not broken her alliance with Russia, her traditional ally since the Soviet era, even though India has greatly improved her relations with the US in order to face China as a common rival. Therefore it would be difficult for Russia to intervene in the Chinese-Indian rivalry, while this is not the case for the United States, because China and the United States are confronting each other at the South China Sea.
China claims most of the South China Sea for herself. The Malacca Straits at the South China Sea are considered as one of the most important energy choke points in the world, since a huge amount of energy and tradable goods pass from it every day.
Map 2 Energy Choke Points
Articles
“The Keys to Closer India-Japan Ties After Abe’s Successful Visit”, January 2016
“India’s Strategic Vietnam Defense Relations”, November 2014
http://thediplomat.com/2014/11/indias-strategic-vietnam-defense-relations/
“India, Indonesia to Cooperate on Maritime Security, Defense Procurement”, August 2015
“Australia, India step up defence ties”, September 2015
http://www.sbs.com.au/news/article/2015/09/03/australia-india-step-defence-ties
“Pakistan hands management of strategic Gwadar port to China”, February 2013
http://www.reuters.com/article/us-pakistan-port-idUSBRE91H0IU20130218
“South Korea and India to boost defence ties, infrastructure finance”, May 2015
http://in.reuters.com/article/southkorea-india-modi-visit-idINKBN0O30VO20150518