Mosques and market streets teem with evening crowds tempted by the scent of syrupy sweets and hefty rice plates, as more than half a billion Muslims across southern Asia break the day’s Ramadan fast. The Islamic holy month began over the weekend and during that time believers abstain from eating, drinking, smoking, and sexual relations between sunrise and sunset. The fast is conceived as a spiritual struggle against the seduction of earthly pleasures — but for the nightly “iftar” meal, festive meals traditionally bring families together and there is intense social activity. The centuries-old …