NEW DELHI: In a major step towards sustainable fashion, researchers at IIT Delhi have developed a method to recycle denim waste into high-quality knitted garments without compromising on comfort or durability.
At a time when India produces nearly 3.9 million tonnes of post-consumer textile waste annually, most of which ends up in landfills, this innovation offers a promising solution to one of the fashion industry’s most pressing environmental problems.
The research, led by professor Abhijit Majumdar and professor B S Butola from the Department of Textile and Fibre Engineering, addresses a key challenge in textile recycling: the loss of fibre strength and length during mechanical processing, which usually results in inferior fabrics. By optimising the recycling process, the team was able to minimise damage to fibre properties while converting discarded denim into a yarn that retained its quality.
These yarns were then used to create knitted garments through seamless whole-garment technology, with recycled fibre content ranging from 25% to 75%. The breakthrough finding: up to 50% recycled yarn can be used without any noticeable difference in the feel or quality of the final product.
“To reduce the roughness of recycled yarns, a softening treatment was applied to the fabric,” explained Majumdar. “This ensured that the tactile feel of the garments matched that of virgin textiles.”
Importantly, the process is not limited to denim. “We have demonstrated our work with denim waste, and it can be extended to any other textile waste,” he added.
Beyond material innovation, the team also examined the environmental benefits of their approach. Using Life Cycle Assessment (LCA) in the Indian context, PhD scholar Satya Karmakar collected data from the Panipat textile recycling cluster to measure the impact.
The analysis showed that recycling denim waste using this method can reduce greenhouse gas emissions, acid rain, and fossil fuel depletion by 30–40%, and ozone layer depletion by up to 60%. Additionally, the method reduces dependence on virgin cotton, which is highly resource-intensive, contributing to 24% of global warming impact during its cultivation due to high usage of pesticides, fertilisers, and water.
The findings have been published in the Journal of Cleaner Production, and the team is now working on the next frontier: exploring whether textile waste can be recycled multiple times without significant degradation.