people were unjustly persecuted to death. Despite this, Shanghai maintained economic production with a positive annual growth rate. The Shanghai People's Commune was established in the city during the January Storm of 1967. Since 1949, Shanghai has been a comparatively heavy contributor of tax revenue to the central government; in 1983, the city's contribution in tax revenue was greater than investment received in the past 33 years combined. Its importance to the fiscal well-being of the central government also denied it from economic liberalizations begun in 1978. In 1990, Deng Xiaoping finally permitted Shanghai to initiate economic reforms, which reintroduced foreign capital to the city and developed the Pudong district, resulting in the birth of Lujiazui. As of 2020, Shanghai is classified as an Alpha+ city by the Globalization and World Cities Research Network, making it one of the world's Top 10 major cities. In early 2022, Shanghai experienced a large outbreak of COVID-19 cases. After localized lockdowns failed to stem the rise in cases, the Chinese government locked down the entire city on April 5. This resulted in widespread food shortages across the city emerged as food-supply chains were severely disrupted by the government's lockdown measures, which was not lifted until June 1. Geography Shanghai is located on the Yangtze Estuary of China's east coast, with the Yangtze River to the north and Hangzhou Bay to the south, with the East China Sea to the east. The land is formed by the Yangtze's natural deposition and modern land reclamation projects. As such, it has sandy soil, and skyscrapers have to be built with deep concrete piles to avoid sinking into the soft ground. The provincial-level Municipality of Shanghai administers both the estuary and many of its surrounding islands. It borders the provinces of Zhejiang to the south and Jiangsu to the west and north. The municipality's northernmost point is on Chongming Island, which is the second-largest island in mainland China after its expansion during the 20th century. It does not administratively include an exclave of Jiangsu on northern Chongming or the two islands forming Shanghai's Yangshan Port, which are parts of Zhejiang's Shengsi County. Shanghai is located on an alluvial plain. As such, the vast majority of its land area is flat, with an average elevation of . Tidal flat ecosystems exist around the estuary, however, they have long been reclaimed for agricultural purposes. The city's few hills, such