what is china upto ?

I was reading this news item on TOI today of China placing a ban on Indian Steel. The amazing thing is this - India has hiked steel prices by Rs 300/tonne. This is causing Chinese buyers to shell out an extra $500 million. A quick math reveals that India is approx shipping 72 ($500 * 43 / 300) million tonnes of steel. And that makes only the third largest supplier for China.

72 million tonnes of existing supplies. I am guessing the total yearly supplies should be a lot more (will try and find that out). But the bigger question is - what is China building with all this steel ?

Update:
Some stats from http://www.issb.co.uk/

Chinese Imports of Iron Ore increased 19% year-on-year in 2006 to 326.3
million tonnes. Australia supplied 126.8 million tonnes up 13% on
2005's 112.2 million tonnes
Brazil overtook India to supply 76.4 million tonnes up 40% on 2005's 54.7
million tonnes
Indian exports increased only 9% from 68.6 to 74.8 million
tonnes