My comp has asked me 2 sign an indemnity bond in lieu of increment is it legal in india.?

My employer wants me to sign an indemnity bond in liue of the increment and promotion.This has not been mentioned at the time of joining(one year back).they have promised me an increment after six months but now after one year they are giving a handsome increment of 30% only when i sign indemnity agreement for one year.Also they are modifying the notice period from 1 month to three month.I wanted to know that does that bond has any legal implications on me if i leave the job abrubtly after signing the bond as i need increment.Indemnity bond is made on a100 rs stamp paper.they have mentioned that in case of breach of indemnity bond i have to pay thre month of salary +150000+12% tax from the date of breaching the bond.Pls tell me how can i deal with the situation as i need increment an d i also dont want to get strucked with bond.