Explanation:

Background: The Dual System of Government in Bengal was the brainchild of Lord Clive.The Diwani (Fiscal) was carried out by the company so Company was Diwan.The Nizamat (territorial) jurisdiction was carried out by these decrepit Indians so they were Nizam.So, this system of separate Diwan and Nizam is called Dual Administration. However, the real authority was East India Company in the Nizamat also.The biggest fall out of this system was that the Indian Merchants were reduced to beggars.On the one side, British kept enjoying the duty free trade; the Indian merchants were to pay around 40% of the revenue.The peasants were now under the British revenue collection.
Learning: After the abolition of the Dual System, the responsibility of collecting the revenue fell on the shoulders of the Company.For that purpose, a Board of Revenue was established at Calcutta to supervise the collection of revenue.English Collectors were appointed in each district. This is the foundation stone for the present day collectorates.The treasury was removed from Murshidabad to Calcutta and an Accountant General was appointed. Calcutta thus became the capital of Bengal in 1772 and shortly after of British India.