The principle that 'law as well as justice should try to prevent unjust enrichment' is a fundamental tenet of equity and contract law, ensuring fairness and preventing one party from unfairly benefiting at the expense of another. Unjust enrichment occurs when a person retains money or benefits which in justice and equity belong to another. The Indian Contract Act, 1872, though primarily dealing with express contracts, incorporates this principle through its provisions on 'certain relations resembling those created by contract,' commonly known as quasi-contracts.

Understanding Unjust Enrichment: Unjust enrichment is not based on a contract (agreement between parties) but on the principle of equity and natural justice. It arises when:

1. A person has received a benefit.
2. The benefit was at the expense of another person.
3. It would be unjust for the person to retain that benefit.

The law intervenes to compel the person who has received the benefit to restore it to the person from whom it was received, thereby preventing 'unjust enrichment.'

Relevant Provisions in the Indian Contract Act, 1872 (Sections 68-72): These sections deal with situations where the law imposes an obligation on a party, even in the absence of a formal agreement, to prevent unjust enrichment. They are often termed 'quasi-contracts' because they create obligations similar to those arising from a contract, but without the element of offer, acceptance, and consideration.

1. Section 68: Claim for necessaries supplied to person incapable of contracting, or on his account. This section states that if a person, incapable of entering into a contract (like a minor or a person of unsound mind), or anyone whom he is legally bound to support, is supplied by another person with necessaries suited to his condition in life, the person who has furnished such supplies is entitled to be reimbursed from the property of such incapable person. The underlying principle is that the supplier should not suffer a loss, and the incapable person should not be unjustly enriched by receiving necessaries without payment.

2. Section 69: Reimbursement of person paying money due by another, in payment of which he is interested. When a person who is interested in the payment of money which another is bound by law to pay, and who therefore pays it, is entitled to be reimbursed by the other. For example, if a tenant pays the landlord's municipal taxes to prevent his property from being sold, the tenant can recover the amount from the landlord. The landlord would be unjustly enriched if he did not reimburse the tenant.

3. Section 70: Obligation of person enjoying benefit of non-gratuitous act. If a person lawfully does anything for another person, or delivers anything to him, not intending to do so gratuitously, and such other person enjoys the benefit thereof, the latter is bound to make compensation to the former in respect of, or to restore, the thing so done or delivered. For instance, if a tradesman accidentally delivers goods to the wrong address, and the recipient consumes them, the recipient is bound to pay for them. This prevents the recipient from being unjustly enriched by consuming goods without payment.

4. Section 71: Responsibility of finder of goods. A person who finds goods belonging to another, and takes them into his custody, is subject to the same responsibility as a bailee. While not directly about payment, it implies an obligation to return the goods to the true owner, preventing the finder from unjustly enriching themselves by keeping someone else's property.

5. Section 72: Liability of person to whom money is paid, or thing delivered, by mistake or under coercion. A person to whom money has been paid, or anything delivered, by mistake or under coercion, must repay or return it. For example, if a bank mistakenly credits an amount to a customer's account, the customer is obligated to return it. Retaining the money would constitute unjust enrichment.

These provisions collectively demonstrate the Indian Contract Act's commitment to the principle of preventing unjust enrichment, ensuring that no one benefits unfairly at another's expense, even in situations where a formal contract does not exist. They uphold the broader principles of justice, fairness, and equity in commercial and personal dealings.