Expats are often surprised and confused when someone wishes them “Good evening” at 4:30 pm!
Well, the fact is that in India, between 4 pm and 8 pm is considered to be evening.
The division of the day is as follows:
4 am – 12 pm Morning
12 pm – 4 pm Afternoon
4 pm – 8 pm Evening
8 pm onwards – Night
It might have to do with fact that in West, days last much longer in Summer, whereas in India its usually dark by 7 pm on an average.
Between 4 and 6 am in the morning is the best time for Yoga and Meditation. It is called Brahma Muhurt (Time belonging to Brahma, the God of Creation), and therefore considered a part of morning (when people are supposed to wake up and start daily activities with yoga, puja, etc) and not night.