Muhammadan law applies to: (a) Muslims by birth, and (b) Muslims by religion, i.e., persons who have become converts to Islam.
In India, Muhammadan law is applied as a branch of personal law to the Muslims in matters relating to Inheritance, Succession, Wills, Gifts, Wakfs, Marriage, Dower, Divorce, Paternity and Guardianships. In other matters, the general laws of the land, as for instance the Law of Torts, the Indian Penal Code, the Indian Contract Act, etc., apply.
The Courts in India apply those rules of Muhammadan law:
(i) Which have been expressly directed to be applied to Muslims, except in so far so as they are altered or abrogated by the Indian Legislature? (Thus, for instance, the rule of Muhammadan law that a convert from Islam is to be excluded from inheritance is abolished by the Freedom of Religion Act, 1850);
(ii) Which, though not expressly directed to be applied, are not excluded by the Indian Legislature, either expressly or by implication? These rules are applied as matter of equity, justice and good conscience. No rules of Muhammadan law that have not been expressly directed to be applied can be applied if they have been abolished, either expressly or by necessary implication.
Thus, for instance, rules of Muhammadan law with regard to pre-emption are not applied in U. R and Punjab, because there are special Acts dealing with these topics in those states. Similarly, the rules of Muhammadan Criminal law or the Islamic law of Evidence are not applied; rather, the matter is governed by the Indian Penal Code and the Indian Evidence Act.
In the mofussil areas of the erstwhile State of Bombay (now Maharashtra and Gujarat), the law to be applied in the trial of suits was to be Acts of Parliament and Regulations of Government applicable to the case; in their absence, the usage of the country in which the suit arose was to be applied; if none such applied, the law of the defendant, and in the absence of any specific law and usage, justice, equity and good conscience alone would govern the case. [Sec. 26, Bombay Regulation of 1827 (Regulation IV)]