NRO Interest - Taxed at source and in Foreign Country

Hi Friends.

I have a query regarding tax on Interest Income across India and UK 

I have NRO FD Income which is generating Interest Income  on a monthly  basis - following are the taxes applied

1. TDS of 30% deducted in India on interest income (which will need to be claimed back after a year through return)
2. Tax of foreign savings in UK @ 40% and only 15% can be claimed back as tax relief (DTAA)

This means for an NRI this is very tax inefficient as taxes are levied twice and waiting time to get tax refund. Also shouldnt income generated in India not be taxed just once (in India) 

Questions are :

1. How does DTAA provisions allow for interest income to be only taxed in India (and not in UK)
2. What are the other alternatives to generate interest income in India and have it only taxed in India
3. What are other alternatives to NRO FD to generate income in India

Thanks

Sidd