Company asking for 1l if not joined

There is no impediment in accepting the better offer. Legal notice to pay is of no legal effect. Does the offer letter contain any arbitration clause?

Have you signed the offer letter accepting such a condition of paying Rs.1 lakh for verification?

The condition of imposing cost of one lakh for selection process/ verification is invalid and illegal, better to get it amended /deleted from contract of your service.

The agreement or the condition to pay Rs. 1 lakh towrds the charges for background verification may be a convenient clause to the company but they may not be able to invoke the clause legally to recover the amount without any legally liable debt in it.

If they issue a legal demand notice you may give a reply denying the allegations and refuse to pay the same.

If they still approach court, you can challenge them legally because no such claim is  legally maintainable

it mentions : The offer letter shall be governed by and construed in accordance with the laws of India. You and the Company hereby expressly agree that the Courts at Chennai, Tamilnadu shall have exclusive jurisdiction for any matters arising out of this offer letter.