Gratuity Deduction - deducting 4.8%. Which one is correct percentage?

Respected Umakanthan.M Sir
There are 2 case
1.Mohan has worked for 8 year in a company .and his basis salary was rs 25000/- and after 6 years they reduced his basic salary up to 18000/- though his gross salary remained same.
now after 8 year mohan has resigned and smoothly given the hand over .
on which basis salary he will get his gratuity .
2. Ashish join company from 2014 and Gratuity monthly amount considered in his CTC but he left job after 3 year then what about his gratuity amount which was deducted from his monthly salary

Dear friend,
In Mohan's case, he can claim and get gratuity under the Payment of Gratuity Act only on the sum total of the basic and D.A drawn by him in the last month of service only. He can not agitate the issue of reducing his basic after his resignation.
The deduction from Ashish's monthly salary towards gratuity is certainly an illegal deduction. He can file a claim in the Labour Court u/s 33C-2 of the Industrial Disputes Act, 1947 for recovery of the amount deducted so far.