Daily Working Hours, Overtime Compensation

Hello, I have a question regarding daily work hours and compensation for overtime work. I am an employee in a company providing a computer based service to clients, and I am based in Bangalore, Karnataka. According to my understanding, I am required to stay within the office from lets say, 7AM to 5PM (10 hours a day), of which I need to be putting in at least 8 hours of productive work per day, provided my assigned client has work for me lasting 8 hours or more. Apparently, I am entitled to 1 hour of break per day, subject to my clients schedule as well, with a minimum of 20 minutes up to an hours accordingly. In my current situation, I have been ordered to enter the office at 6:45AM and more often than not, leave by 4:40PM to 5PM on most days. I have gone beyond 6PM on certain days as well. And with most days, I continuously put in work for 7 hours continuously, without a break as my client does not have a scheduled break period, and does not inform me of the same. This inherently does not allow me to take a break for what could be 6-8 hour stretches at a time, with only high-risk laden bathroom runs. So far, I have not been assigned any colleague, and it not in the company's best interest to assign a colleague, to help me with my work. Regular work days are from Monday to Friday, and I am entitled to only publicly declared holidays in India, and business holidays of the United States of America. My questions are the following, 1) In Karnataka, what is considered as a regular work hour/ minimum daily work hours in an office setting? 2) What gets considered as overtime, when I work for more more than the daily work hours, considering I do not get a lunch break or even restroom breaks. 3) What kind of compensation am I entitled to? Am I legally entitled to en-cash it? 4) Company policy is to pay me the same amount of compensation for working on a Saturday as they would compensate me on a regular working weekday. Is this legal? 5) Is it legal for the company to introduce a policy where I cannot en-cash work during a holiday/Saturday and I will only be entitled to get an earned leave?