Under the diwani of the East India Company, Bengal's economy faced a crisis due to various factors. The British policies and actions had a significant impact on the economic situation of Bengal during this time.

1. **Drain of Wealth**: The British implemented policies that led to the draining of wealth from Bengal. They imposed heavy taxes and levies on the local population, which resulted in the impoverishment of the people. The revenue extracted from Bengal was used to finance the British colonial administration and the purchase of goods from Europe, leading to a drain of wealth from the region.

2. **Monopolistic Trade**: The British East India Company had a monopoly over trade in Bengal. They controlled the production and sale of goods, which allowed them to manipulate prices and exploit the local producers. The British traders exported raw materials from Bengal at low prices and imported finished goods at high prices, leading to an unfavorable balance of trade for the region.

3. **Deindustrialization**: The British policies also contributed to the deindustrialization of Bengal. They discouraged local industries and handicrafts to protect their own industries in England. The traditional industries of Bengal, such as textiles and metalwork, were severely impacted, leading to unemployment and economic decline.

4. **Land Revenue System**: The British introduced the Permanent Settlement in Bengal, which fixed the land revenue at a high rate. The zamindars (landlords) were made intermediaries between the British and the local peasants, and they exploited the peasants by charging exorbitant rents. This system resulted in the concentration of land in the hands of a few wealthy landlords and increased agricultural distress.

5. **Famine and Poverty**: The British policies and land revenue system contributed to widespread poverty and famine in Bengal. The high land revenue demands and exploitative practices led to the dispossession of peasants from their land and increased rural poverty. During periods of drought or crop failure, the peasants were unable to pay the high rents and taxes, leading to famine and starvation.

Overall, under the diwani of the East India Company, Bengal's economy faced a crisis due to the drain of wealth, monopolistic trade, deindustrialization, the exploitative land revenue system, and the resulting famine and poverty. These factors severely impacted the economic well-being of the region and led to the impoverishment of the local population.