Meridional profiles of OI 6300 ¿ nightglow emission measured using a scanning photometer over Cachoeira Paulista, a low latitude station, often show propagating patches of airglow disturbances with north to south and west to east velocity components, occurring mostly in the premidnight period. 132 measurements carried out during a period of 26 months since January 1978, show significant seasonal dependence in the occurrence of these disturbances, with most of the events occurring in the spring-summer months and with very rare occurrence during the winter solstice. The north to south propagation velocities lie in the range of 150 to 350 m/s. A case by case comparison of the occurrences of these airglow disturbances with simultaneous ionograms over Cachoeira Paulista show that almost the totality of these disturbances are accompanied by strong range type echoes in the ionograms and vice versa. These results therefore support our earlier contention that these types of airglow disturbances might be manifestations of the equatorial plasma bubbles.