The Indian Railways at present have commissioned and are operating 27 sections as Green Corridors. All the trains plying on these sections are running with all the coaches equipped with bio-toilets.
Thus, there is no direct discharge of human waste from the trains running on these Green Corridors.
Indian Railway has provided about 1,25,000 bio-toilets in its coaches till March 2018.
The 'Bio-Toilet project' of Indian Railways is an innovative and indigenous development of technology. This technology is first of its kind being used by any railroad in the world for On-board accelerated digestion of human waste. These bio-toilets are fitted underneath the lavatories and the human waste discharged into them is acted upon by a colony of anaerobic bacteria that convert human waste mainly into water and small amounts of bio-gases.
The gases escape into atmosphere and waste water is discharged after chlorination onto the track. Human waste, thus, does not fall on the railway tracks thus improving cleanliness and hygiene at platforms, and facilitate track and coaches maintenance staff to perform their work more efficiently. The Bio-toilet project is aligned with 'Swachh Bharat Mission', launched by Prime Minister Narendra Modi.
The technology for Bio-toilets have been innovated, designed and is 'Made in India'. It has been developed jointly by Indian Railways' Engineers & DRDO's scientists. It is one example where the technology developed for defence applications has been utilised for civilian purpose.
With the proliferation of bio-toilets in 60%, coaches commensurate human discharge in open has been eliminated.