I guess every change in OI means, contract traded between buyer and seller. But then why change in OI and volume have different number in option chain? could you please provide with some example.
Open Interest tells you how many contracts are outstanding (active) in the market. It’s little tricky to explain, you can read this chapter on Varsity to better understand Open Interest.
While Volume indicates Total Buy and Sell transactions happened over period of time.
Eg: Nifty 10700CE has Open Interest of 10, those 10 open contracts can change hands throughout the day 100 times, so Volume for that specific day will show 7500 (100 = Contracts Traded * 75 = Lot Size)
Still I am not clear and could you please give explain with the uploaded example. As per you statement volumes should be higher that volumes, but true is Change in OI is higher than volumes.
Change in OI means total fresh positions opened or closed for the day here it is 928,350 so this are new fresh positions opened.
Now moving to Volume, these are Total Contracts Traded (Bought and Sold) for the day.
It shouldn’t necessary be higher, I was just trying to explain how you will see Volume if you opened chart of a specific option. Look below at Daily Chart of 10600CE you have mentioned above, It has Total Traded Contract’s = 471,337
Here on charts Volume shown is 35.35m for the day, This is counted by multiplying Contracts Traded 471,337 * Lot Size 75 = 35,350,275.
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Thanks, Now I understood 
Hi so these volumes mentioned are for contracts so 471,337 means 471,337*75= 3,53,50,275 shares traded which will always be Higher or equal to OI change.
Volume will be based on Option contracts traded for the day (Contracts Traded * Lot Size), while OI Change means total fresh positions opened or closed for the day.
You can read the below chapters on Varsity to learn more about Volume and Open Interest.