Oh dear how many such gory deaths?
Okay most of the cases of children falling into borewells seem to occur in rural India. This says something about the borewell diameters. In the cities, borewells are dug for domestic purposes. These are lesser in diameter. So looks like the bigger borewells are the problem. Some manufacturing companies too dig large-diameter borewells. These might be typically located in the villages or suburbs.
However, this is not the primary reason – in the villages, people constantly seek groundwater. The moment a farm or company needs water, they try to dig a well. However, open wells are not always the solution (open wells are dug when you have groundwater available easily at shallow depths. Open wells are convenient. But then groundwater is not easily available – thus borewells are dug to a greater depth. Also companies need more water and wells won’t suffice).
People need water and where does that come from? River or lake water supplies is not always available to all areas. Thus, groundwater is the source. And people dig to great depths to get groundwater. Groundwater for various reasons – summer, over exploitation, less recharge etc at times goes down deeper (water table).
However, many of the borewells do not yield water and are “abandoned”. The driller might have used casing and partially sealed the hole. Mostly, though the moment there is no water, the drillers pack up and leave. Vegetation takes over and these borewells are forgotten.
Some day a child wanders over and falls. in. The diameter is enough for the child to fall in. However, it takes time to realize that the lost child could have fallen into the borewell.
The inside of the now defunct or not used borewell might have collapsed. Some bores are 300 feet deep (or more). The child might not always fall to the bottom but get stuck in the mud in between. This is not easy to find out as the hole is dark and deep. It is not a case of just pulling out the child through a vertical shaft.
So rescue operations begin and if the child is closer to the surface, a rescuer gets in and pulls them out. However, if the child has fallen to greater depths, a camera is sent into the hole and then a parallel bore is dug. From there another horizontal bore is dug. Quiet often the rescue succeeds but not always. A lot of Geology is involved and rescue plans must be fast and precise. But even with the best geophysical instruments, it is not easy to estimate the type and size of rock that blocks access to the point where the child is stuck. Moreover, drilling through rock can make the entire borewell collapse.
The simplest solution should be to seal all the holes the moment they are not used. Sadly, this negligence and ineptitude devours a child.