Bangalore Scientists Develop Electronic Nose To Detect Poisonous And Flammable Hydrogen Sulphide Gas Produced From Sewers Sewer pipe line construction in Mumbai. (representative image) (Kunal Patil/Hindustan Times via Getty Images) Scientists from the Centre for Nano and Soft Matter Sciences (CeNS), Bangalore, have developed an electronic nose with biodegradable polymer and monomer that can detect hydrogen sulphide (H2S), a poisonous, corrosive, and flammable gas produced from swamps and sewers. H2S is the primary gas produced from the microbial breakdown of organic matter in the absence of oxygen, and this necessitates easy detection of its emission from sewers and swamps, the Ministry of Science and Technology said in a statement.