My company restructured my job offer with a huge amount of 15 lakhs penalty incase of bond breach

Hi I am 2020 engineering graduate. I have gone through the placements from my college in 3 rd year. where i got selected for two companies in which on of the company @ mu sigma is offered 21 lakhs for 3 year bond. Th structure follows with 3.4 lakh ctc for 1st year. 5.5 lakh for 2nd year and 7 lakh ctc for 3rd year with a bonus of 5 lakhs as soon as joining the company. And the bonus amount@5lakh should be paid back if i break the bond. I was okay with this and attend the drive and got selected for company. I got the joining date also. But because of covid-19 it got postponed and in last month they came up with new compensation structure where i have to pay 15 lakh if i break the bond for 1.5 years and 7.5 lakh for next 1.5 years and 5 lakh for 4th year. They changed the number of years the increased the penalty. The new structure follows @ 40 lakh for 4 years where 10 lakh is considered as training cost. so 30 lakh is the actual amount for 4 years. i have rejected other companies just because of this company before and this came up with the new structure. penalty is of 500% the ctc. is it legal for companies to change the offered compensation and charge such an huge penalty. please look up into this link for more details of offer for better understanding. https://www.techcircle.in/2020/07/07/exclusive-mu-sigma-revises-pay-offer-for-new-hires-sets-rs-15-lakh-penalty-for-employment-bond-breach Do copy and paste the url if not linked directly. This is one of the #trending news all over the employees in india.750+ students carrier is going to get spoiled because of this one company @mu sigma. please do answer is it legal for companies