Traditionally, people of India divided time into 1.5 hour chunks called Muhurthams. Here is a video by a famous Indian Director Naga that explains the concept of time in the Indian perspective. Considering there are multiple 1.5 hour chunks each day, using astrological calculations, Indians determined which time(s) maybe good/auspicious to do some important work, start a new venture, get married, etc. (Guligai.). And they also determined which time(s) may not be good. (Rahu Kaalam, Yama Gandam.)
For each day, there are good times (muhurthams) and bad times, and each time chunk/muhurtham stretches for 1.5 hours. These times are fixed based on the day of the week. Have a look at the below embedded video to understand when these times occur for each day and how to remember the timing. If you do some important work, it has a better chance to succeed if you do it in a good time, is what people of India traditionally believed in.
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