By Ritambhara
Charaka’s chapter on epidemics explains why one disease can strike a whole population at once. It names four shared causes: wind, water, place and time. The chapter is the third in the Vimana Sthana, one of eight books in the Charaka Samhita, the founding text of Ayurvedic medicine.
The Samhita reworks an older compendium attributed to Agnivesha, a pupil of the teacher Atreya. Scholarly estimates place Charaka’s redaction between about 100 BCE and 200 CE. A later physician, Dridhabala, completed missing parts, and the surviving manuscripts descend from his version. The chapter opens with Atreya teaching beside the Ganga near Kampilya, capital of the Panchala country, in the last month of the hot season.
Four things a whole town shares
Agnivesha puts the problem plainly. People differ in constitution, diet, strength, habits, character and age, yet an epidemic kills many of them together. Atreya answers that they share air, water, land and season, and damage to any of these reaches everyone.
The signs he lists are close observations of the environment. Spoiled water, in the 2026 translation by Vitus Angermeier of the Austrian Academy of Sciences, has its “colour, smell, taste or touch” altered, is “full of putrefaction” and “is rejected by water birds”. A spoiled place has crops “bent over, withered, or perished”, winds that are “smoky”, and swarms of “gnats, locusts, flies, mice”. A season turns harmful when its weather runs against the normal pattern.
A ranking by difficulty
Charaka then ranks the four factors. In K. Nishteswar’s translation for the Charak Samhita New Edition, “water is more important than air, and land is more important than water”, and season ranks higher still. Angermeier reads the order as a measure of how hard each factor is to escape. A family can avoid foul air more easily than a failing region or a bad year.
The chapter also gives a practical instruction. Physicians should gather medicinal plants “before the earth becomes infertile”, while their taste and potency remain intact.
Rulers answer for the land
Charaka places the root cause in human conduct. When “the elite of the country, the towns, the market places, and the countryside deviate from dharma”, rain comes late or fails, reservoirs dry up and herbs lose their properties. The language is religious. The logic links bad government to damaged water, crops and health in a single chain of cause. Angermeier notes that epidemics are a theme rarely discussed in pre-modern Ayurvedic literature, which gives this chapter unusual weight.
The first factor today
Air, the first of Charaka’s four factors, still kills on a vast scale in India. The State of Global Air 2025 report, published by the Health Effects Institute with the Institute for Health Metrics and Evaluation, counted more than 2 million deaths in India in 2023 attributable to air pollution. India and China together accounted for 52 per cent of the 7.9 million such deaths worldwide.
Charaka’s chapter treats shared air, water and land as conditions that decide public health, and it assigns responsibility for them to those who govern. It asks today’s readers to judge clean air and water as a duty of authority, measured in lives.
