India uk dtaa

Hey , my

client has his salary income from company both in India and UK . Now thing is, UK taxation authorities have also deducted tax as per their rules and regulations . Do we stand for any benefits under UK and India DTAA ? 

Can he claim the deduction for tax already paid in UK ? 

His status is resident for the relavant financial year . 

Also what rate of exchange is applicable in this case for coversion of UK income to INR