This collection contains data used in paper "Planetary boundary layer height modulates aerosol - water vapour interactions during winter in the megacity of Delhi" (Raj et al., 2021). For detailed description regarding the data please refer to the paper mentioned above. File "AvgCCN.dat" contains campaign average of CCN properties measured in Delhi. File "CCN.dat" contains the time series of CCN properties measured. Column 'H_BL' of that file contain errors, thus please do not use that column, see file "PBL.dat" instead. File "PBL.dat" contains the time series of modelled planetary boundary layer height in Delhi during February to March 2018. File "SD.dat" contains the time series of inverted size distribution data.