Selling house after redevelopment tax implications

Hi

After the new union budget how will tax be calculated on sale of flat after redevelopment. 

My case is as follows

I purchased a flat of 800 sq ft in 2003 for 32 lacs

Then in 2023 my building went into redevelopment. 

Now instead of 800 sq ft my new flat will be of 1000 sq ft

If i follow the new tax that is implemented after the union budget i will be paying a lot of tax

For understanding if i sell the house for 3 cr then as i can not take the benefit of indexation my total tax income will be 3cr less 32 lacs which is 2.68 cr

What can i do to factor in the new tax implications and save tax on house sale. 

I do not intend to buy another house. 

Can i do an agreement with the builder where he can show that the additional 200 sq ft given due to redevelopment has had a cost and my actual cost of the flat is 32 lacs + this x amount. 

Please advice