New Delhi, Sept. 29 -- The Nifty 50 stock index is slated for its weakest monthly expiry in six months on Tuesday amid surging bond yields induced by persistently high crude oil prices.

The bellwether index closed at 22,780.25 on Monday and dropped to a low of 22,569.65 in trading on Tuesday, the expiry day of the September series of derivatives.

The lowest monthly expiry so far this year occurred on 30 March, when the Nifty 50 closed at 22,331.4, a month after the outbreak of the US-Iran conflict. However, the markets recovered from that low to close at 24,334.55 at last month's expiry on 25 August.

NSE derivatives, from which investors take market cues, expire on the last Tuesday every month and weekly expiries happen every Tuesday....