<p>The outbreak of COVID-19 has disrupted the world’s economy and impacted people’s lives significantly. Humanity struggled to combat this pandemic, simultaneously resuming normalcy in techno-economical activities. From a sustainability and energy conservation perspective, curbing the transmission of these respiratory diseases in indoor environments is challenging. To reduce the transmission of these respiratory diseases, the factors affecting the transmission of droplets in indoor spaces, along with proper mathematical modelling and their physics, need serious consideration. Hence, this review discusses the factors influencing indoor transmission, the factors responsible for the virus transmission, and probabilistic research methods. The paper also discusses some deterministic approaches, like CFD models with Eulerian and Lagrangian methods, taken by the researchers to understand the transmission of the particles observing the trajectories of the evaporating droplets. The present finding suggests that Eulerian and Lagrangian provide the spatial distribution of the particle concentration in the air. However, the Lagrangian is preferred over the Eulerian approach as it can track the evaporating droplets and give their trajectories in the air. The focus is on engineering recommendations to mitigate the transmission of SARS-COV-2 in indoor spaces. Appropriate engineering controls like sufficient ventilation, filtration of pathogen aerosols, use of purifiers in synchronisation with ventilation systems, and personal protective equipment are effective ways to reduce the risk of transmission in indoor environments. The major challenge is optimising energy consumption in indoor environments with existing infrastructure. This review will be helpful to both the public and agencies in combating respiratory disease transmission in indoor environments.</p>