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Stratosphere-troposphere Exchange (STE) is an important factor controlling the budget of ozone in the upper troposphere and lower stratosphere. Studies of STE events in India are so far restricted to co-ordinated campaigns, and measurements over longer periods are relatively scarce. In the light of this observation, this paper aims to identify the Indian latitudes most likely to be affected by STE, the frequency of occurrence of shallow and deep STE events, the depth up to which the ozone from the stratosphere descends into the troposphere during STE events and the resultant trend of ozone in the troposphere under the possible influence of STE over the 24 years from 1982 to 2006. In addition, a case study of the STE of ozone, which occurred during a cut-off low event at Athens, Greece, is presented in order to understand the parameters that may contribute to the evolution of these events. It is concluded that STE plays a minor role in the Indian tropospheric ozone budget. On the whole, the occurrence of STE events in India is found to increase with increase in latitude and occur more frequently during winter followed by summer. The occurrence of deep STE is higher at high latitudes while the occurrence of shallow STE is higher at low latitudes.

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En años recientes, los episodios de contaminación del aire han sido motivo de gran preocupación a nivel mundial, dado el incremento tanto en su frecuencia como en su intensidad. Un episodio particularmente alarmante de alta contaminación se observó en algunas partes de la India entre los últimos días de octubre y los últimos días de noviembre de 2016. El índice de calidad del aire pasó de deficiente a muy malo en el norte y oeste de la India, mientras que fue de satisfactorio a moderado en el sur y el este. En este trabajo se analizan las causas de este episodio de alta contaminación. Aparte del efecto Diwali en la contaminación del aire, los hallazgos del estudio indicaron la importancia de la quema de biomasa sobre la India.