<p>Variations in ionic profiles and chemical characteristics viz. aerosol liquid water content (ALWC) and in situ pH of fine aerosol plausibly caused by crop residue burning (CRB) over the North-Western Indo-Gangetic Plain were studied. Ambient PM_2.5 samples were collected and criteria air pollutants were obtained for Amritsar, Punjab, from September to December, covering pre-CRB and CRB phases. These samples were analyzed for water-soluble ionic species. Further, Extended Aerosol Inorganics Model (E-AIM) model II was used to calculate ALWC and in situ pH. PM_2.5 concentrations increased significantly from 48.5 ± 22.6&#xa0;μg m⁻³ (pre-CRB) to 77.6 ± 24.3&#xa0;μg m⁻³ during CRB, showing a 60% increase during the CRB phase. Scaling analysis revealed that while gaseous pollutants (NO₂, SO₂) were primarily amplified by meteorological trapping, the surge in PM_2.5 was driven by a 2.7-fold increase, from 23 ± 36 (pre-CRB) to 63 ± 88 (CRB), in fire detection counts. Chemical characterization of water-soluble ionic species showed a doubling of the biomass burning marker K⁺ from 746&#xa0;ng m⁻³ to 1367&#xa0;ng m⁻³ and a significant rise in secondary inorganic aerosols, particularly nitrate (NO₃⁻), which increased from 198&#xa0;ng m⁻³ to 2439&#xa0;ng m⁻³. Charge balance analysis revealed an alkaline aerosol nature, with neutralization pathways shifting from terrigenous dust (Ca²⁺, Mg²⁺) to anthropogenic (NH₄⁺ + K⁺) during the CRB phase. Interestingly, the median value of ALWC increased significantly (<i>p</i> = 0.002) from 6.18&#xa0;μg m⁻³ (pre-CRB) to 16.48&#xa0;μg m⁻³ (CRB). However, no significant variation in in situ pH was observed between pre-CRB and during CRB periods. This could be attributed to internal changes observed in the ionic profiles of fine aerosol due to CRB emissions.</p>