Zero Liquid Discharge (ZLD) is increasingly used to control industrial wastewater where water scarcity, receiving-water vulnerability, high salinity, or judicial and regulatory pressure make conventional discharge unacceptable. In India, however, ZLD is often discussed as though it were a uniform statutory obligation across industries. This critical review re-examines that assumption by integrating peer-reviewed evidence on ZLD and brine management with India's statutory framework, sector-specific standards, judicial principles, and selected industrial-cluster experience. The analysis shows that the Water (Prevention and Control of Pollution) Act, 1974, and the Environment (Protection) Act, 1986, primarily establish consent, standards, and enforcement architectures; ZLD emerges through sectoral notifications, consent conditions, administrative directions, and judicial intervention rather than from a single nationwide ZLD statute. Technologically, high water recovery can reduce freshwater abstraction and liquid discharge, but the final concentration step shifts burdens toward energy use, greenhouse gas emissions, scaling and fouling control, and salt or hazardous residue management. Evidence from Tiruppur illustrates both the pollution-control gains and institutional costs of rapid ZLD adoption, whereas the Jajmau tannery cluster demonstrates the continuing importance of common effluent treatment and targeted ZLD components rather than a one-size-fits-all model. The review therefore proposes a tiered decision framework in which mandatory ZLD is reserved for high-risk settings and, elsewhere, is complemented by minimal liquid discharge (MLD), fit-for-purpose reuse, resource recovery, common infrastructure, and enforceable discharge limits. The central policy implication is that wastewater regulation should target environmental outcomes across the water-energy-carbon-waste nexus, not merely the absence of a liquid outlet.