Capital gain on residential property

Hi Experts,

Please guide me on following Capital Gain issue

My client has purchased Residential Property in Jul 2012, demolish it and started construction in 2013. In 2016 almost 90% construction complete, and they sell the same in Apr 2016.

They purchased one other residential plot in May 2016 of the long term capital gain calculated.

Is the LTCG exempt or taxable?

He will construct the residential plot within 3 years.