Innocent passage is a fundamental right granted to all ships, regardless of flag, to navigate through the territorial sea of a coastal state, provided the passage is 'innocent'. This right is enshrined in the United Nations Convention on the Law of the Sea (UNCLOS) of 1982, to which India is a signatory.

Definition and Conditions of Innocent Passage: Article 17 of UNCLOS states that ships of all states, whether coastal or land-locked, enjoy the right of innocent passage through the territorial sea. Article 18 defines 'passage' as navigation through the territorial sea for the purpose of traversing it without entering internal waters, or for proceeding to or from internal waters or a roadstead call. The passage must be continuous and expeditious, though stopping and anchoring are permitted if incidental to ordinary navigation or rendered necessary by force majeure or distress.

Article 19 specifies that passage is 'innocent' so long as it is not prejudicial to the peace, good order, or security of the coastal state. It lists activities that are considered prejudicial, including any threat or use of force, any exercise or practice with weapons, any act aimed at collecting information to the prejudice of the defense or security of the coastal state, any act of propaganda, launching or landing of aircraft or military devices, loading or unloading of any commodity, currency or person contrary to the customs, fiscal, immigration or sanitary laws, and any act of willful and serious pollution. Submarines and other underwater vehicles are required to navigate on the surface and show their flag during innocent passage.

Indian Position on Innocent Passage: India's position on innocent passage, particularly concerning warships and submarines, has been a subject of discussion and is generally aligned with a more restrictive interpretation of UNCLOS provisions, emphasizing the coastal state's security interests. While India recognizes the right of innocent passage for all ships, it has historically maintained that the passage of foreign warships and submarines through its territorial sea requires prior notification or authorization. This stance is rooted in the belief that the passage of military vessels, especially those capable of carrying weapons or conducting surveillance, could be 'prejudicial to the peace, good order, or security' of the coastal state if conducted without its knowledge or consent.

India's Territorial Waters, Continental Shelf, Exclusive Economic Zone and Other Maritime Zones Act, 1976, and subsequent notifications, reflect this position. While the Act generally permits innocent passage, it grants the Central Government the power to regulate such passage, especially for warships and submarines. India's view is that while UNCLOS Article 19 defines what constitutes 'non-innocent' passage, it does not explicitly state whether prior notification or authorization is required for warships. Many coastal states, including India, interpret this silence as allowing them to impose such requirements as a measure to ensure the 'innocence' of the passage and protect their security.

This interpretation often contrasts with that of major maritime powers, such as the United States, which advocate for a broader interpretation of innocent passage, asserting that no prior notification or authorization is required for warships. This difference in interpretation highlights a persistent tension between the freedom of navigation and the sovereign rights and security concerns of coastal states.