Uniform buffer zones versus site-specific Zones of Influence: critically examine which approach better balances wetland conservation and urban development in India.

The Pallikaranai marsh in Chennai is a Ramsar site of about 1,247.5 ha [2], and it shows the dilemma clearly. The NGT imposed a 1-km construction ban around the marsh. The Tamil Nadu State Wetlands Authority (TNSWA) now proposes an interim Zone of Influence (ZoI) of only 128.19 ha across 36 survey numbers [1]. In principle, the site-specific approach is better. In practice, it works only when science and deadlines back it.

Uniform buffers: strengths

• Precautionary certainty: a uniform buffer is simple to enforce and hard to dilute, in line with Articles 21 and 48A.
• Immediate protection where data is lacking: the NGT's 1-km ring froze construction at Pallikaranai's edges [1]. The Supreme Court's 2022 directions on a 1-km Eco-Sensitive Zone around protected areas followed the same logic.

Uniform buffers: weaknesses

• Ecologically blunt: water moves along channels and low ground, not in circles. The marsh is hydrologically linked to about 54 satellite water bodies [2].
• Economic freeze: a blanket ring also restricts lawful private land with no water link to the wetland. Builders such as CREDAI-Chennai have challenged it through writ petitions [1].

Site-specific ZoI: strengths

• Statutory design: the Wetlands (Conservation and Management) Rules, 2017 require each wetland's zone of influence to be delineated, with activities prohibited or regulated within it [3].
• Function-based: a site-specific zone can protect what matters most, such as the marsh's role as a "sponge" and aquatic buffer for flood-prone Chennai [2].
• Planning clarity: maps at the survey-number level let the CMDA build the line into its master plans.

Site-specific ZoI: weaknesses

• Evidence gap: the High Court admits that a final ZoI needs "elaborate studies" [1], yet the site has been designated since April 2022 [2].
• Risk of capture: the interim zone is about one-tenth of the site's area, and the petitioners call it "completely acceptable" [1]. Agreement among the parties does not prove ecological adequacy.
• Fragmentation: 36 scattered plots may leave the marsh's inflow channels exposed.

Verdict and way forward

• Prefer the site-specific ZoI, but set a time-bound final ZoI and publish how the zone is drawn.
• Keep the uniform buffer as the default until the ZoI is notified.
• Back the ZoI with sewage control and an Integrated Management Plan under the NPCA.

A uniform buffer gives certainty without precision; a site-specific ZoI gives precision only when it rests on evidence. Hydrology-based, time-bound ZoIs that are written into master plans can serve both Article 48A and SDG 11 and SDG 15. They would let Indian cities grow without paving over their wetlands.