Question

what is meant by dyarchy system?when this system was started?

Answer 1

The principle of dyarchy was a division of the executive branch of each provincial government into authoritarian and popularly responsible sections. The first was composed of executive councillors, appointed, as before, by the crown. The second was composed of ministers who were chosen by the governor from the elected members of the provincial legislature. These latter ministers were Indians.
dyarchy, also spelled diarchy, system of double government introduced by the Government of India Act (1919) for the provinces of British India.

Answer 2

Dyarchy. Dyarchy, also spelled diarchy, system of double government introduced by the Government of India Act (1919) for the provinces of British India. It marked the first introduction of the democratic principle into the executive branch of the British administration of India.