The question concerns the location of Village Dongla in Madhya Pradesh, which Indian astronomers are considering for establishing a new mean time called 'Dongla Mean Time (DMT)'. The options provided are Dewas, Ujjain, Dhar, and Barwani. Let's explore these options and the specific context for the solution.

Correct Answer: Ujjain

Ujjain is a famous historical city located in the Ujjain district of Madhya Pradesh. It has been an important cultural and scientific center, traditionally associated with astronomy in India. Ujjain is significant in Indian history due to its geographical alignment, which has made it an important reference for time calculations.

Reasoning:

• Ujjain was one of the primary meridians used in ancient India for astronomical calculations.
• The village of Dongla is located near this historical and scientific hub, making it a suitable site for establishing a mean time reference.
• Proximity to Ujjain provides geographical validity and cultural significance for choosing Dongla for the establishment of DMT.

The other options (Dewas, Dhar, and Barwani) do not have the same historical and scientific significance concerning Indian timekeeping and the study of astronomy as Ujjain does.

Therefore, the correct answer is Ujjain, as Village Dongla is situated in this district.