As you mentioned, that your institution’s reputation is being slandered by your competition by voicing out false claims and unruly accusations, you can begin by sending out a legal notice, which voices your concerns and grievances alongside notifying the recipient about your intentions to undertake certain legal proceedings. This serves as a formal communication between both parties and acts as a last warning to the receiver to fulfil a certain condition if he does not want a court battle.
Now, even if this doesn’t prevent the individual to curb his/her practices, you can file a case for defamation. In India, defamation is both civil and criminal offence. The remedy for a civil defamation is covered under the Law of Torts. In a civil defamation case, a person who is defamed can move either high court or subordinate courts and seek damages in the form of monetary compensation from the accused. The Indian penal Code, 1860 provides an opportunity for the defamed person to file a criminal case against the accused. Under sections 499 and 500 of the IPC, a person guilty of criminal defamation can be sent to jail for two years.
Though it is suggested that if such a situation arises, you proceed with a civil suit and seek damages with the assistance of a local lawyer.
Hope this helps you.