Defara Dhanya, Jakarta – Research scientist at the Climate and Atmosphere Research Center of the National Research and Innovation Agency (BRIN), Erma Yulihastin, revealed the data on wind direction and speed around the Bandung Islamic University (Unisba) as well as the neighboring Pasundan University on Monday evening, September 1, 2025.
Erma's response came following the claim that the police did not fire tear gas into the campus area on late Monday.
"The personnel shot tear gas on the road, which was then blown by the wind into the Unisba parking lot," said the Head of Public Relations of the West Java Regional Police, Chief Commissioner Hendra Rochmawan, on Tuesday, September 2, 2025.
The police statement invited scrutiny on social media, pointing out the similar pattern previously seen during the Kanjuruhan tragedy in Malang, East Java, in October 2022, where at least 135 people died after the police fired tear gas inside the stadium. The blame was then shifted to the direction of the wind.
Meanwhile, in Bandung, video footage circulating on social media clearly showed the police chasing protesters into the two campuses and firing tear gas. As a result, dozens of people fainted at Unpas ground, with dozens of bullet casings found inside the campus.
Due to the disparity between the police's claim and the video footage, Erma offered, "Shall I help check the wind movement?" She posted this through her social media account X last Tuesday afternoon.
Wind movement around Unisba and Unpas
Erma then revealed the data on wind direction and speed based on the automatic weather station (AWS) located in Sukaluyu, 2-3 kilometers away from Unisba. According to the climatology professor, the data from the AWS could already represent the weather conditions in the area of the Unisba and Unpas campuses.
"Surface winds generally have the same pattern within a radius of 2-3 kilometers," said Erma, who was contacted again on Thursday afternoon to confirm her statements.
According to Erma, if Unisba were to install its own weather measuring instrument, it would be even better for data collection. She added, "This is the importance of installing Personal Weather Stations in every strategic building/complex, as it can serve as undeniably valid evidence."
Based on the data series from AWS Sukaluyu, the wind was very weak (0-4 km/h) at the time of the incident, at around 11:00 p.m. to 12:00 a.m. local time. "According to the theory, the wind in the middle of the night is overall weak inland, unless there is a weather disturbance. Therefore, the wind direction is no longer important since the speed is weak," explained Erma.
The same data also showed that from until dawn breaks on September 2, there was no significant gust of wind. "The recorded wind gust of 14 km/h was only in the afternoon at around 03:00 p.m."
– Vedro Imanuel Girsang contributed to the writing of this article