•Development of NiO-SnO2/CMC coated cotton fibres.•Efficient catalyst for the reduction of organic/inorganic pollutants.•Reusability of designed catalyst for three cycles. A nanocomposite of nickel oxide and tin oxide (NiO-SnO2) was prepared by mixing with carboxymethylcellulose (CMC) and coated on natural cotton fibers (CF). NiO-SnO2 coated CF (NiO-SnO2/CF) was examined as catalyst for decolorization and reduction of different water contaminants. NiO-SnO2/CF showed the highest rate constant (1.1087 min−1) for methylene blue (MB) reduction. Thus, comparative reduction study showed that NiO-SnO2/CF is a stable and best catalyst for MB reduction. With the increase of the amount of catalyst from 10 to 15 mg, the 98% reduction of MB was achieved in 4.0 and 3.0 min, respectively, Moreover, MB concentration, amount of reducing agent, stability and recyclability were investigated and optimized. NiO-SnO2/CF appeared to be a best catalyst for efficient removal of MB because it retained superior catalytic activity, stability and recyclability in the reduction reaction of MB. The advantage of the developed NiO-SnO2/CF catalyst is that it can be simply retrieve by easy towing out from reaction media which is the main advantage of using the CF support. The developed nanocatalyst gives a new cost and time effective material and route for efficient reduction of MB for environmental safety.