It had initially been suggested that a window be left open in all BTS trains to circulate air in order to curb the spread of Covid-19. However, an experiment found that leaving a window open did not help with the ventilation and instead created heat within the train carriages.
Officials said that enough air is circulated when the train doors open to pick up or drop off passengers and rides between stations take no more than two or three minutes.
They also said that leaving a window open will inconvenience passengers now that the rainy season has arrived.