Notice periods and bonds are contract questions, and the Indian Contract Act, 1872 sets the boundaries.
Notice periods
Your notice period comes from your contract or, where applicable, the state Shops and Establishments Act. A contractual notice period is generally enforceable in the sense that leaving early is a breach, but an employer cannot force you to keep working. The practical consequences of leaving early are usually financial: recovery of notice pay if the contract allows buyout by either side, or withholding of a relieving letter, which matters mostly because the next employer asks for it.
If your contract allows the employer to pay you in lieu of notice, courts read symmetry into these arrangements less often than employees hope, so what your specific clause says matters more than what feels fair.
Bonds and training agreements
Two rules do most of the work here. First, Section 27 of the Contract Act makes agreements in restraint of trade void, so a clause that simply stops you from joining a competitor after employment ends is generally unenforceable in India. Second, Sections 73 and 74 govern what an employer can actually recover when you break a bond: reasonable compensation for loss actually suffered, not automatically the number written in the bond.
That means a training bond is not automatically illegal. If the employer genuinely spent money training you, they can claim the reasonable, provable cost of it. What they cannot usually do is recover a punitive round figure with no relationship to real expenditure, or hold you in the job against your will.
Before you resign
Read the exact clause. Note whether buyout is permitted, what the bond says was spent on you, and whether the employer can document it. Most bond disputes are won or lost on whether the employer can prove actual cost.
This article is general information, not legal advice, and does not create a lawyer-client relationship. For a review of your clause and your options, start the intake.