IIT Delhi researchers have developed a process to recycle denim waste into high-quality knitted garments without losing comfort or durability. By optimising fibre recovery and using seamless whole-garment technology, the method can incorporate up to 50% recycled yarn with no compromise in quality.
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In a major step towards sustainable fashion, researchers at IIT Delhi have developed a technique to recycle denim waste into high-quality knitted garments while maintaining comfort and durability.
With India producing nearly 3.9 million tonnes of post-consumer textile waste annually, most of which ends up in landfills, this innovation addresses one of the fashion industry’s most pressing environmental challenges.
The research, led by professor Abhijit Majumdar and professor B S Butola from the Department of Textile and Fibre Engineering, tackles a key hurdle in textile recycling: the loss of fibre strength and length during mechanical processing, which usually results in lower-quality fabrics. By optimising the recycling process, the team minimised damage to fibre properties while converting discarded denim into yarn that retained its quality.
These yarns were then used to create knitted garments using seamless whole-garment technology, with recycled fibre content ranging from 25% to 75%. The key breakthrough: up to 50% recycled yarn can be used without any noticeable difference in the texture or quality of the final product.
“To reduce the roughness of recycled yarns, a softening treatment was applied to the fabric,” said 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 assessed the environmental benefits of their approach. Using Life Cycle Assessment (LCA) in the Indian context, PhD scholar Satya Karmakar gathered data from the Panipat textile recycling cluster to measure the impact.
The analysis showed that recycling denim waste through this method can reduce greenhouse gas emissions, acid rain, and fossil fuel depletion by 30–40%, and ozone layer depletion by up to 60%. It also lowers dependence on virgin cotton—a crop responsible for 24% of global warming impact during cultivation due to its heavy use of pesticides, fertilisers, and water.
The findings have been published in the Journal of Cleaner Production, and the team’s next goal is to explore whether textile waste can undergo multiple recycling cycles without significant loss of quality.
The global textile waste problem
The IIT Delhi breakthrough comes at a time when the global fashion industry faces mounting criticism for its environmental footprint. Over 100 billion garments are produced each year worldwide, with a large proportion ending up in landfills or being incinerated. According to the US Environmental Protection Agency (EPA), 17 million tonnes of textile municipal solid waste were generated in 2018 alone. The fashion industry is widely regarded as one of the most polluting sectors after oil, contributing to resource depletion, greenhouse gas emissions, and water contamination.
This massive waste problem is compounded by fast fashion trends, which encourage overproduction and rapid consumption cycles. The environmental toll is severe—not just in terms of waste generation, but also in the excessive use of water, energy, and chemicals during textile manufacturing.
Textile recycling: An urgent solution
Textile recycling offers a practical pathway to address this challenge by diverting waste from landfills, reducing pollution, and lowering resource consumption. The process involves recovering fibre, yarn, or fabric and reprocessing these materials into new, usable products.
Textile waste is generally classified into two main types:
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Pre-consumer waste – Manufacturing offcuts, rejected fabric rolls, and unsold stock.
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Post-consumer waste – Discarded garments, household textiles, and other fabric products.
In recent years, many countries have introduced stricter regulations to curb textile waste, prompting companies to create products from post-consumer waste and recycled raw materials, including plastics. Academic studies show that textile reuse and recycling provide far greater environmental benefits than incineration or landfilling, making them integral to sustainable fashion.
Why IIT Delhi’s innovation stands out
While textile recycling is not new, a major limitation of conventional methods is the deterioration of fibre strength and length, resulting in coarse and less durable fabrics. IIT Delhi’s approach overcomes this by refining the mechanical recycling process to preserve fibre properties, making it possible to produce garments that meet the quality expectations of consumers.
The seamless whole-garment technology used in the project further enhances the appeal of recycled garments by reducing seams, improving comfort, and optimising production efficiency. The softening treatment applied to the fabric ensures that the tactile feel is on par with virgin textiles—a critical factor in consumer acceptance.
The scalability of this method is another advantage. Since the process is not limited to denim, it could be applied to other textile waste streams, including cotton blends, polyester fabrics, and home furnishings, potentially transforming India’s textile recycling industry.
Looking ahead
The IIT Delhi research marks a promising milestone, but it also raises important questions for the future of textile recycling—particularly whether fibres can be recycled multiple times without losing performance. If this challenge is addressed, the fashion industry could move significantly closer to a closed-loop system, where waste is continually reprocessed into new garments.
With global attention increasingly focused on sustainability, such innovations will be critical in reshaping the fashion supply chain. By coupling advanced recycling methods with responsible production and consumption practices, the industry can move towards a more circular and less wasteful future.
