Tax treatment on interest paid on late payment of gratuity

I am paid interst on late payment of gratuity. The gratuity amount is approx.Rs. 8.9 lakhs. The interst paid is Rs. 3.5 lakhs approx. My penssion income is Rs. approx Rs. 33000 per month. I am retired and my present age is 64 years completed in JUly 2018.

Will the interest paid on  late payment of gratuity attract any income tax? Is it exepmpted from income tax like gratuity? Will it be treated as income from other sources and add to the total income from pension? What will be the treatment of income tax on the interest?

Is there any provision to save tax on such income?