Every evening NSE publishes the bhavcopy — the official record of the day: OHLC, volume, trades and deliverable quantity for every listed security. Almost every EOD screener, chart and stock page in India is built on this one file.
Per security per day: open, high, low, close and previous close; total traded quantity and turnover; number of trades; and (via the companion delivery report) deliverable quantity — the basis of delivery percentage. Corporate-action-adjusted series, 52-week ranges and averages are all computed downstream from accumulated bhavcopies.
The bhavcopy publishes in the evening after close — typically from around 4 PM onward. Any "daily" statistic dated today is only final after that file lands. VolumeLens ingests it automatically each evening and regenerates its stock pages and daily screeners afterwards, which is why those pages always show an explicit "data as of" date.
Live quotes during the session are provisional from a daily-statistics standpoint: the close isn't the close until the session ends, and delivery data doesn't exist until settlement reporting. EOD analysis built on bhavcopy trades a few hours of latency for finality and official numbers.
Usually from around 4:00-4:30 PM IST on trading days, with the delivery report alongside or shortly after.
Yes — NSE publishes it publicly. The work is in ingesting, cleaning, adjusting and computing derived statistics across years of files.
Differences usually come from corporate-action adjustment policies, series selection (EQ vs BE etc.), or one platform using live-snapshot values where another uses the official file.