Fundamental Rights
The State shall not deny to any person equality before the law or the equal protection of the laws within the territory of India.
Everyone within India - citizen or not - must be treated equally by the law, and the law must protect everyone equally. The government cannot arbitrarily favour one person or group over another without a reasonable, lawful justification. Courts have interpreted this to strike down laws or government actions that are arbitrary, unreasonable, or discriminatory.
If a government office processes applications faster for people who pay a bribe, or a public sector bank official refuses to act on your fraud complaint because of your background rather than the facts of your case, that is a violation of Article 14's equal-treatment guarantee.