A groundbreaking analysis of air quality inside long-distance buses in India has delivered encouraging news for passengers. The study found that travellers spend a significant majority of their journey time—up to 80%—breathing air with particulate pollution levels deemed generally acceptable.
Key Findings from the Real-Time Monitoring Study
The analysis, a collaborative effort between climate-tech firm Respirer Living Sciences and IntrCity SmartBus, was conducted from December 7 to 14, 2025. It involved real-time monitoring across 11 intercity routes, providing the first publicly shared evidence of what passengers actually breathe during road travel in India.
The core finding is that for most routes, 60-80% of the journey time, the concentration of harmful PM2.5 particles remained below the 60 micrograms per cubic meter (µg/m³) threshold. This indicates that air quality conditions inside the buses were largely acceptable during transit and were notably cleaner than typical winter ambient air in many north and central Indian cities.
Specific routes such as Delhi-Kanpur, Pune-Nagpur, Pune-Bangalore, Delhi-Lucknow, Pathankot-Delhi, Delhi-Katra, and Katra-Delhi performed exceptionally well, with PM2.5 levels staying below 60 µg/m³ for more than 80% of the travel time.
Identifying Pollution Spikes and Intermittent Risks
While the overall picture is positive, the study did identify variations. Routes like Delhi-Pathankot and Lucknow-Delhi showed slightly higher PM2.5 levels, with concentrations exceeding 60 µg/m³ for more than 20% of the travel time.
However, researchers emphasized that exposure to very high pollution levels (above 90 µg/m³) was typically limited. For many buses, such high-pollution episodes accounted for only below 10-15% of the total travel time. These spikes were described as intermittent, likely caused by short-term external factors like traffic congestion or passing through localized pollution hotspots.
"This dataset marks a turning point in how we understand air quality during intercity journeys," said Ronak Sutaria, Founder and CEO of Respirer Living Sciences. "Pinpointing the specific stretches where exposure spikes allows for targeted interventions, whether through modified ventilation settings or operational adjustments."
The Impact of Smart Air-Purified Bus Fleets
The study was enabled by the deployment of India's first air-purified intercity bus fleet, SmartBus.AQI. This initiative integrates Respirer's AI-powered air-quality monitoring and filtration technology into select IntrCity buses to actively target pollutants like PM2.5, carbon dioxide, dust, and smoke.
During the 15-day study period, an estimated 4,500 passenger journeys took place on the monitored buses. The technology's effectiveness translates to a meaningful reduction in respiratory health risks for these travellers, especially during North India's peak winter pollution.
"Every clean kilometre matters. We're not just measuring numbers; we are reducing exposure for thousands of travellers," Sutaria added. Manish Rathi, CEO and Co-Founder of IntrCity, noted that passengers can view real-time AQI data onboard and via the app, bringing unprecedented transparency to in-transit air quality.
The partnership addresses internal findings that in-bus pollution can be two to three times higher than safe limits, driving the need for cleaner air systems on high-pollution corridors. This study provides a crucial new dimension to national conversations on mobility, public health, and technological innovation in combating air pollution.
