I will be travelling from seattle to kolkata via china. Is visa required?

I will land at Shanghai 6.05pm, Dec. 10. After 2h55min layover, I will leave shanghai at 9:00pm, and reach KMG 1.00AM, Dec. 11. Then, i will leave KMG at 11.50pm. Dec. 11 for kolkata.
I will not go out of any airports. Do I need visa? if yes, then how could I get it? please guide me
I am at seattle. My tickets cannot be changed
i am indian citizen having H1 visa