1. Changes in supply and demand in the international market: During 2020-2022, affected by the COVID-19 epidemic, the global economic growth slowed down, the supply and demand in the international market were relatively loose, and the prices of commodities such as sugar generally fell. This may lead to the decrease of investors' interest in white sugar futures, thus affecting the trading volume.

2. Domestic policy adjustment: In 2020-2022, the domestic sugar market in China was affected by policy adjustment. For example, in 2020, the China government began to implement a new sugar management policy and strengthen the supervision of the sugar industry, which may lead to a decline in investors' confidence in sugar futures and affect the trading volume.

3. Investor's mood fluctuation: The trading volume of futures market is not only affected by market supply and demand, policy adjustment and other factors, but also affected by investor's mood. For example, in 2020-2022, affected by domestic and international economic situation, policy changes, epidemic situation and other factors, investor sentiment may fluctuate, thus affecting the trading volume of the futures market.