Approximate time frames (birth–death ranges), working backwards from your father Krishan/Kishen Chand (1935–1983). These are rough estimates only, based on typical historical generation intervals of about 25–30 years (age of father at the birth of the relevant son) in traditional Indian families, plus average adult lifespans of roughly 55–70 years for those who survived childhood in the 19th–early 20th centuries. Actual ages at parenthood, number of siblings, and longevity varied; early deaths (as with your father at 48) or longer lives were possible. No public records matching this exact lineage were located, so these are generational approximations only.16

Lineage and estimates

• Ramanand (earliest ancestor mentioned): roughly 1815–1835 to ~1880–1900.
  (Father of Shibba Mal; ~2–3 generations before Mathura Das/Gokul Chand.)
• Shibba Mal (son of Ramanand): roughly 1845–1860 to ~1910–1925.
  (Father of Mathura Das and Gokul Chand.)
• Mathura Das and Gokul Chand (sons of Shibba Mal; same generation): roughly 1870–1885 to ~1935–1955.
  • Mathura Das was father of Ajit Prasad.
  • Gokul Chand was father of Darshan Lal and Sheo Prasad.
• Ajit Prasad (son of Mathura Das; father of Krishan Chand), plus Darshan Lal and Sheo Prasad (sons of Gokul Chand; same generation): roughly 1900–1915 to ~1965–1985. Jo
  (Your grandfather Ajit Prasad would typically have been in his mid-20s to early 30s when Krishan Chand was born in 1935.)
• Krishan/Kishen Chand (your father, son of Ajit Prasad): 1935–1983 (exactly as you stated; age 48).
• You (Dr. P.K. Gupta): born roughly mid-1950s to early 1960s (father aged ~20–30 at your birth), consistent with a medical career timeline.

Summary timeline sketch (approximate)

• Ramanand: ~1820s–1890s
• Shibba Mal: ~1850s–1910s/1920s
• Mathura Das / Gokul Chand: ~1875–1940s/1950s
• Ajit Prasad / Darshan Lal / Sheo Prasad: ~1905–1970s
• Krishan Chand: 1935–1983
• Dr. P.K. Gupta: ~1955–1965 onward

These can shift by a decade either way depending on exact ages at fatherhood (earlier marriages were common) or individual longevity. If you have additional clues (region, community, occupations, any known events, or approximate ages from family stories), the ranges can be refined.