Why pandas_market_calendars Fails for Indian Markets (and what to use instead)

Indian algo traders and quant developers hit the same wall: they reach for pandas_market_calendars , set up XNSE , and get back answers that are silently wrong for three segments that matter most in India. Here is what breaks and what to use instead. The three failure cases 1. MCX evening sessions MCX commodity markets (crude oil, natural gas, gold, silver) run until 23:30 IST. pandas_market_calendars has no MCX calendar. Any check after 15:30 returns a wrong answer. # pandas_market_calendars — no MCX at all # mcal.get_calendar("MCX") → KeyError # aion-indian-market-calendar — works correctly from aion_indian_market_calendar import IndiaMarketCalendar from datetime import datetime from zoneinfo import ZoneInfo cal = IndiaMarketCalendar . bundled ( 2026 ) tz = ZoneInfo ( " Asia/Kolkata " ) cal . is_market_open ( " MCX " , datetime ( 2026 , 6 , 18 , 20 , 0 , tzinfo = tz )) # True 2. NSE Currency Derivatives (CDS) — wrong hours, wrong holidays USDINR, EURINR, GBPINR, JPYINR futures and options trade on NSE CDS from 09:00 to 17:00 IST — 90 minutes longer than NSE equity. CDS also has a separate holiday calendar. pandas_market_calendars has no CDS calendar. Using XNSE gives you wrong close times and potentially wrong holiday answers for any currency derivative workflow. from aion_indian_market_calendar import IndiaMarketCalendar cal = IndiaMarketCalendar . bundled ( 2026 ) # These resolve correctly to their respective segments cal . is_market_open ( " USDINR " , at ) # NSE_CURRENCY_DERIVATIVES: closes 17:00 cal . is_market_open ( " NSE " , at ) # NSE_EQUITY: closes 15:30 cal . is_market_open ( " MCX " , at ) # MCX: closes 23:30 3. Muhurat trading (Diwali special session) On Diwali, NSE runs a one-hour equity session in the evening. pandas_market_calendars marks this day as a holiday. Schedulers that rely on it will skip execution entirely. cal = IndiaMarketCalendar . bundled ( 2026 ) events = cal . events_on ( " 2026-11-08 " , exchange = " NSE " ) # Returns the Muhurat t