Precautions before land purchase from builder in a township.

Hi,

I'm planning to purchase a plot from a builder in a 50 acer township under construction lucknow UP, Though the builder claim that Project is approved by authorities i.e. LIDA and 143 done. What documents I should check and how to verify those before putting my money.

As per the builder Project is yet to be approved by the banks.

Thanks!

Abhi