Useful life as per companies act

Hi Jatin, please clarify what is the nature of business of the company for which solar energy plant and ZLD plant is used.  

If such plant is used in generation, transmission and distribution of power then Solar power plants are not explicitly mentioned in Schedule II of the companies act however for what I have seen in other companies having Solar power plants is that they take useful life of 25 years. I am attaching the financial reports of Azure Power ltd which has filed its financial statements in SEC in US where in Page F-13 (or Page 127) in Notes to accounts they have mentioned that they have taken useful life to be 25 years, However such is totally debatable as I am not getting the basis for such life.