As you would know that the normal shifts used to be 12 hours for all the jobs and granted most of the jobs were productions or mining jobs earlier but you get my drift. People fought and fought a bit more to make the 8-hour shift that's a standard now but unfortunately, that isn't the case for everyone. Maybe try talking to the humble guard standing or sitting outside your office entrance whom you have borrowed from an organization. The guards and other support staff are asked routinely to do 12 hours shifts maybe legally but more than likely illegally the company is charged for 3 8-hour shifts but then 2 guys cover the shifts in a day saving the company cost of 1 guard and the 2 guys covering 12-hour shifts they may or may not be paid for the extra 4 hours.
And that's the case for all the MNCs all around India so I would count myself lucky that I am asked to work only a 9-hour shift with a 1-hour break and have to clock 40 hours for a week and not something different. But then comes another notion where if you spend more time in the office it's considered more productive while it's anything but that. My brother works in a big MNC as a product manager and during the times when a product is being launched, he routinely works 14 - 15 hours to monitor the calls and complains all the time. How can you expect anyone to be productive when you ask them to do 15 hours shifts with no off time. But that's the norm and that's that is.
I don't know what kind of chaos would erupt when 4 day work week is introduced in India, it's already a reality in a few countries and the result is increased productivity and happiness levels in the population. But who cares about the populations and the workers. We are just a cog in the machine and we have never worried about the machines.