The objective of the thesis is to reduce the cooling load of the offices in Delhi, India by integrating passive strategies and low-ex cooling (evaporative) technology through facades as a decentralized ventilation system. The cooling demand in India is going to increase up to 8 folds by 2030. Almost 50% of the energy is spent on space cooling for offices in Indian climatic conditions. In order to reduce the cooling demand alternative low ex cooling technologies are being researched and implemented. In this thesis, various types of evaporative cooling and their various properties and its application on Delhi’s climatic scenario and its limitations were studied as one of the low-ex techs. The study concludes by choosing Dew-point indirect evaporative cooler because of its high wet bulb effectiveness with no addition of humidity. For continuous operation, the humidity in the air needs to removed before supplying it to the cooler. So, the design involves a combination of Dew-point Indirect evaporative cooler (D-IEC) coupled with Desiccant coated heat exchanger (DCHE). The system also requires a source for heating and cooling down the water for Regeneration cycle and Dehumidification cycle, evaporative cooler respectively. The cooling demand of the building needs to be addressed by multiple devices in a decentralized ventilation system. The total number of devices required determines the cost of installation and ease of maintenance over the years and it depends on the cooling load. So, it is necessary to reduce the cooling demand of the building using passive strategies before integrating the evaporative cooler. The building’s cooling load has been reduced to 50W/m2 by adapting suitable passive strategies like shading systems, reducing U values of walls, glazing and roof, reducing infiltration and the internal heat gain. The above-mentioned strategies result in 146.41kWh/m2/yr with a water-based chiller (CENTRALIZED), and it is efficient when compared to the recommended national figure of 180 kWh/m2/yr. But using the De-VAP systems (DECENTRALIZED) cuts down the energy by even much further to up to 40% (92.26kWh/m2) in which almost 1/3rd of the energy can be generated by installing PV on the roof. This design takes us further one step closer to the NET ZERO building.