Xian reminds me irresistibly of Delhi. It is, I think, the broad streets, the dryness, the shop-fronts with their small canopies leaning out over the pavements, the bicycle-riding white-shirted population—it is too hot to wear the otherwise ubiquitous thin blue cotton jackets—and, most of all the city wall, the presence of history. The only other place where I have had a similar sense of déjà vu is Shanghai. There the intolerable density of population, the sluggish river crammed with boats and sewage, and vestiges of British commercial architecture combine to create an atmosphere evocative of Calcutta. Beijing and Nanjing, the two cities I know best, remind me of nothing but themselves.