SCMP journalists in Shanghai report on the ongoing lockdown in the Puxi district. Thomas Yau discusses rising tensions among residents amid supply shortages, why he’s bartering noodles for toothpaste and anger directed at local neighbourhood committees. Tracy Qu analyses China's food delivery companies responding to the food crisis while authorities seek to quell social media unrest. Shanghai-based sustainability expert Richard Brubaker analyses supply chain bottlenecks and when the West will…