SHANGHAI, Jan 12 (Reuters) - China stocks rebounded on Tuesday from their biggest pullback in three weeks in the previous session, while the blue-chip CSI300 index closed at its highest in nearly 13 years. ** The Shanghai Composite index ended 2.18% higher at 3,608.34, while the blue-chip CSI300 index closed up 2.85% at 5,596.35 — the highest since Jan. 15, 2008. ** The smaller Shenzhen index ended up 1.76% and the start-up board ChiNext Composite index was higher by 2.829%. ** Aviation sector was among the biggest winners after the civil aviation regulator said passenger traffic will recover 90% to the pre-COVID-19 level as part of its goal for 2021 at the annual meeting on Tuesday. ** Shares of China Aerospace Times Electronics Co Ltd hit their daily upward limit at the close. ** Consumer staples were also among top gainers after posting sharp losses a day earlier. A gauge tracking financials jumped 3.58%. ** Around the region, MSCI’s Asia ex-Japan stock index was weaker by 0.45%, while Japan’s Nikkei index closed up 0.09%. ** However, some investors were worried about a pickup in coronavirus infections in northern China and Sino-U.S. tensions. ** Authorities in China introduced new COVID-19 curbs in areas surrounding Beijing on Tuesday, putting 4.9 million residents under lockdown as new infections raised worries about a second wave in a nation that has mostly contained the disease.