i have seen too many places about bitcoin halving but nowhere found a good understanding. so wanted a clear explanation.
Halving is the cutting down of the miner's block reward into half which will cause the reduction of the allocation rate of new coins generated daily and miners reward but halving was the technique used in crypto to current price/market inflation and for the betterment of the market price.
I hope the OP already read the post of coingecko as the graph will give him a clear understanding on what is happening during halving. But would be nice to see also the corresponding price on the graph so we will see how much bitcoin's price changes during those times of halving. Though we already know that the price really increased after halving but this time, I don't think the performance in terms of increase will be similar in previous halvings.
it is not going to be similar cause it can surpass the past increase?

If you are going to look at the chart and see the history for halving there's always a pump every halving and this time it's actually happening again! If you are updated at the price of bitcoin is jumps from 6900 to 8700 in just one week! So I am sure that the halving this year is gonna be awesome and will actually surpass the past halving's when it comes to bitcoin price.