 The study uses continuous wavelet transform to determine periodicity and local modulations in aerosol optical depth, AOD, at 35 locations in India, revealing annual, quasi-bionnual oscillations, QBOs, semi-annual and quasi-triennial oscillations. The observed periodicities are consistent with seasonal and yearly cycles of variations in AODs, while the QBO-type periodicity is non-stationary and the annual period is stationary. The study also finds that phase relations among different locations reveal that modulations in AOD over a location region can influence aerosol characteristics over other locations' regions. This article was authored by S. Ramachandran, Seyantan Ghosh, Amit Verma, and others.