Mathematical modeling of the human body is an important topic for research, and extensive work has been going on since the 1940s. The current study aims to develop a comprehensive thermoregulation model, particularly for Indian reference subjects. An improved model with 800 nodes is developed, incorporating more details than the existing models for Indian subjects. A general thermoregulation model consists of two interacting systems- The active and passive systems. Here, the Passive system is modeled with reasonable parameters from either derivation or literature review. The Active system generates thermoregulatory responses as per environmental conditions, which directly affects the passive system and thus, thermoregulation is achieved. The Indian model developed is used to obtain thermal responses under transient ambient temperature with and without introducing a clothing layer. Validation of the model is attained from available experimental results for Indian subjects. The transient ambient temperature analysis revealed that Indians are more temperature-sensitive. The Indians are more prone to shivering than Western subjects. It is also noted that the Indians undergo more sweating, nearly 1.25 to 2.5 times than Western. The results of the clothed analysis are in agreement with the physical properties of the clothing layer.