Options on NSE, like Nifty options or equity options also possess open interest at different strike prices. The accounting of open interest in options is the number of open positions or unsettled positions of a particular option instrument of a specific strike price, with a pre-determined expiry.
Option writing refers to selling of the option contract, writers are the one who bring options into existence by selling them. Just like Insurance contracts come into existence by Insurance companies selling them.
The Market views differ but unlike Option Buyers Not only one of the two (Up or Down) directions, But also No move helps option writer.
While Call Buyers' Bias = Bullish
Call Writers' Bias = Neutral to Bearish
While Put Buyers' Bias = Bearish
Put Writers' Bias = Neutral to Bullish
This brings us to an interesting inference
Call Writers' Expectation = Stock/Index =< Strike Price or Stock/ Index Rise could be Capped at Strike Price
Put Writers' Expectation = Stock/Index => Strike Price or Stock/ Index Fall could be Floored at Strike Price
On the other hand, Call Undwinding / Put Unwinding could also be seen as lowering Writers' Interest a.k.a. confidence in aforementioned Capped or Floored Strike Price
Call Unwinding (especially where OI is highest) = Expectation of Higher Cap or More room to Rise
Put Unwinding (especially where OI is highest) = Expectation of even lower Floor or More room for Fall
This can be conveniently observed in the OPEN INTEREST tool of Quantsapp, where the red bars indicate open interest of Nifty put options and green bars indicate the open interest of Nifty call options, as indicated in the template ahead.