Four cub scout troops and one boy scout troop against a division of Marines. I'll take the marines.
China could kick India's ass in week, finish up with the cousins and be back in Bejing for the NBA finals.
China is going forward with this because they are so much more powerful than the Indians. Their economy is 5 times larger and their military technology is 20 years ahead of India. A fight between India and china at this point would be like a child fighting a grown man.
This dam has strategic implications. Once complete, China would be able to effectively shut down the bramaputra river and halt the livelihoods of around 100 million Indian peasants. Any Indian government in power could be significantly destabilized when it serve’s china’s national interests to do so. China isn’t trying to fight India. These moves are prep work to turn India into a compliant client state.