RIYADH: As millions of Muslims gather in Makkah for Hajj, concern is growing over the environmental toll of one of the world’s largest annual religious gatherings — particularly the vast quantities of plastic waste left behind. From water bottles to shopping bags, single-use plastics are a staple at major public events, and Hajj is no exception. Given the sheer volume of pilgrims, this waste can have lasting environmental consequences, unless mitigated by more sustainable choices.