Textile dyeing accounts for up to 20 per cent of global industrial water pollution, a figure widely cited by researchers and sustainability bodies, including in a landmark review of textile wastewater treatment published in the Journal of Environmental Management. For manufacturers and brands navigating a rapidly tightening regulatory environment—such as the EU's Ecodesign for Sustainable Products Regulation (ESPR) - it is increasingly a liability to manage, a cost to reduce, and a competitive differentiator to own. In dyeing, wastewater is not merely an environmental problem; it can also represent paid-for chemistry, process water, heat, and treatment capacity going down the drain.
The stakes for India are considerable. The textile and apparel industry contributes approximately 2 per cent of GDP, accounts for around 10–11 per cent of manufacturing output, and provides direct employment to over 45 million people—the second-largest employment generator after agriculture. Textile and apparel exports stood at UD$35.87 billion in FY2023–24, with India holding the second-largest textile manufacturing capacity globally and a 3.9 per cent share of world textile exports.
The question is no longer whether dyeing processes need to change. It is whether the industry will drive that change proactively, on its own terms, or be forced into it reactively, at far greater cost and with far less control over the outcome.
The Environmental Cost of Dyeing
The pressure on textile dyeing is intensifying because the process has remained largely unchanged for decades despite its well-documented environmental footprint.
The dominant method for colouring cellulosic fibers, cotton, viscose, modal, lyocell, is reactive dyeing. Reactive dyes form covalent bonds with the cellulose fiber, which is why they produce such a vibrant, wash-durable colour. But there is a fundamental electrochemical problem at the heart of the process. Both the dye molecule and the cellulose fiber surface carry a negative charge. They repel each other. To overcome this repulsion and drive the dye toward the fiber, conventional processes rely on large volumes of salt, typically sodium chloride or sodium sulphate, added to the dye bath. This is not a workaround or a shortcut. It is the standard approach, used at industrial scale across dyehouses worldwide.
Even when enough salt is used, a considerable proportion of the applied dye does not bond to the fiber. Instead, it hydrolyses in the bath and cannot be fixed. This means a portion of the dye purchased by the mill never becomes product value; it becomes colour load in the wastewater stream. This unfixed dye must then be removed through repeated washing and soaping cycles at elevated temperatures—more water, more energy, more time, and more effluent generated to remove dye that failed to fix. These post-dyeing wash steps are among the most resource-intensive stages in textile manufacturing, generating coloured, chemically complex effluent that places a significant burden on wastewater treatment systems. Research published in Dyes and Pigments has documented the central role of auxiliaries, including salts, in driving this cycle of resource consumption.
In India, the scale of this burden is well documented. Tiruppur, the country's largest knitwear cluster and home to 729 textile dyeing units alone generates an estimated 96.1 million liters of dyeing wastewater per day (PubMed / CPCB study). The Noyyal River became a cautionary example of textile-sector pollution. In Tiruppur, dyeing effluent pushed total dissolved solids (TDS) levels in the Orathupalayam dam to 4,250–7,900 mg/L , far above India’s drinking-water benchmark of 500 mg/L acceptable and 2,000 mg/L permissible only where no alternative source exists. In 2011, the Madras High Court ordered the closure of non-compliant dyeing and bleaching units, affecting around 720 units, 40,000–50,000 workers, and reportedly causing ₹50 crore per day in industry losses. The crisis forced Tiruppur to retrofit treatment capacity through CETPs and ZLD systems; official reporting later noted 16 of 18 CETPs operating.
The Noyyal, Yamuna, Godavari, and Ganga are among the rivers most visibly affected by textile dyeing discharge, where untreated or inadequately treated effluent has rendered stretches of water have been associated with reduced suitability for agriculture and domestic use, with reported environmental and potential public health impacts (Down to Earth, March 2025). Over 70 CETPs currently operate across Indian textile clusters including Tirupur and Surat, but the treatment burden itself driven by the multiple washing steps to remove hydrolysed dyes remains embedded in the conventional dyeing process.
Brands and consumers increasingly share concerns about the water-intensive nature of conventional dyeing and the growing treatment burden it places on wastewater infrastructure. The cost of dyeing down the drain is therefore more than environmental; it is economic and operational.
