I live in Bengaluru, so the scene is that here the big lakes are actually all man made “bunds”. Essentially, they are rain water harvesting structures that follow the natural creeks along their drainage basins. Along intervals there are these “check dams” that stop the flow of water and create artificial lakes along the path of the creek. When monsoon comes, the rainwater falls atop the highest point (which is the center of the city by design), and drains into these lakes, one lake overflows into another and this process goes on. Andrew Millison himself has made quite a few videos on this subject, he explains this better than I could.

Now the situation in Bengaluru is that we receive plenty of rainfall in the monsoon, as does most of the subcontinent, but the traditional rainwater harvesting lakes have been filled over with concrete to build apartments. Fewer lakes overall mean more pressure on the existing lakes, when the large ones overflow uncontrollably we get floods like in 2022. So to answer your question, water itself is plenty, but most of it comes in the monsoon months as rain so we need to store it somewhere, be it in lakes or in wells. Not to mention “open” wells are a two-way exchange, during monsoons of heavy rainfall the wells recharge and store water in the shallow water table.

At the end of the day mankind always ends up using resources, no? It just depends on whether it is sustainable or not.

I think this may be the way the explanation comes across. Historically, there were many lakes, but now the lakes don’t exist because there’s a large city there instead. So, to replicate the behaviour of the lakes, you need to get the water to traverse rock to remove some impurities and then settle in aquifers.