Covid-19’s Delta variant is proliferating world-wide threatening unvaccinated populations and economic recovery. WSJ breaks down events in key countries to explain why Delta spreads faster than previously detected strains. Composite: Sharon Shi The recent surge in Covid-19 cases in Southeast Asia has throttled ports and locked down plantations and processors, sparking extended disruptions of raw materials such as palm oil, coffee and tin. Restrictions in Malaysia , the world’s second-largest producer of palm oil, have prevented migrant laborers from traveling to plantations, raising prices of the ubiquitous edible oil used to make candy bars, shampoo and biofuel.