Which is the hardest trek in the entire Indian Himalayas?

Chadar trek is a high altitude Himalayan trek that requires more than 10 days of trekking. It is one of the hardest treks in the entire Himalayas and is considered to be extremely difficult because you have to trek on the frozen Zanskar river in winter when the temperature varies between -20°C and -40°C. The difficulty level of this trek is very high and hence it requires a lot of endurance and stamina. You are required to have some previous trekking experience and hence beginners are not welcomed to a large extent. It is one of such treks that will surely challenge your physical, mental and psychological resistance by throwing unlimited dare on the way. It will certainly bring you out of your comfort zone.