据报道，“热浪”的发生世界各地的情况都在增加。极端高温的增加预计会导致人类的不适程度增加。此外，根据极端高温的严重程度和持续时间，还会造成工作时间的减少、对健康的不利影响和死亡。众所周知，从气象学的角度来说，不仅仅是气温的升高会引起人体不适。温度加上高湿度，低风和不透水的衣服是造成不适的主要原因。最重要的是，在这些不利条件下进行的体育活动的类型是决定一个人所遇到的压力和紧张的重要因素之一。一个多世纪以来，几位科学家对生物气象学进行了研究，并开发了许多热指数，用于量化工作环境中不适或热应激的程度。今天，我们可以从多个来源免费获得观测到的气象参数和相应的模式输出，可用于估计任何地点的热指数值。在这方面，动态和统计降尺度方法都非常有用。 In this study, some of the commonly used heat indices have been calculated for the four major cities of Delhi, Mumbai, Chennai and Kolkata using daily observed parameters from the India Meteorological Department (IMD) for the period 1975 to 2005. Same indices are also calculated based on the simulated values from the Regional Climate Model (RegCM) of the Abdus Salam International Centre for Theoretical Physics (ICTP) over the same period. The RegCM simulated fields have been obtained from the COordinated Regional Downscaling EXperiments (CORDEX) over the South Asia domain. Comparison of characteristics of the four selected indices based on IMD observed data and RegCM simulations leads to the inference that there are several similarities between the two sets of data in terms of their annual cycles and inter-annual variations. This exercise conclusively shows the advantages of dynamical downscaling. Further, results of this study encourage for a comprehensive work in the future for the country wide mapping and projection of heat indices based on model simulations, development of suitable heat indices and classification of comfort classes for their use in warning system for human health related issues in India.