Here is a Hindu headstone at Merville Communal Cemetery. In the autumn of 1915, the town was the headquarters of the Indian Corps. The 6th and Lahore Casualty Clearing Stations were there from the autumn of 1914 to the autumn of 1915.
This headstone is the most traditional, easily-recognisable CWGC design.
Here, in front of the Cross of Sacrifice, are the headstones at Kohima.
Notice how different they are.
Why is this so?
This area of the world is subject to heavy monsoon rains which soak the earth so it's no longer stable. Upright headstones might topple over in the soft mud.
In other areas of the world that are in earthquake zones, the same low-lying design is used.