<p>Understanding of chemical weathering process involved in ionic elution helps in distinguishing the CO<sub>2</sub> sequestration rate at the different micro-climatic setup of Himalayan catchments. In the present study, we have selected three glaciated basins from two different climatic zones of Western Himalayas (Lato and Phutse from the cold-arid zone of Ladakh and Chhota Shigri from the monsoon-arid zone of Himachal Pradesh, India) for determining various solute sources, CO<sub>2</sub> sequestration rate and its control over melt-water quality. Solute sourcing models used in this work shows major cations like Ca<sup>2+</sup>  and Mg<sup>2+ </sup>are from crustal rock-weathering while Na<sup>+</sup> and K<sup>+</sup> sourced out from the sea-salt origin. However, major anions like SO<sub>4</sub><sup>2-</sup> (> 85%) were derived from the crustal origin and HCO<sub>3</sub><sup>-</sup> mostly derived from atmospheric sources (39% to 45 %) in all catchments except HCO<sub>3</sub><sup>-</sup> contribution from carbonation dissolution and silicate weathering is ~29% and ~16% for Ladakh catchments compared to ~9 % and ~29% in Chhota Shigri respectively. The solute model also reveals that the contribution of sulphate oxidative mediated carbonate dissolution (SOCD) in HCO<sub>3</sub><sup>-</sup> flux is relatively higher in Chhota Shigri (~16%) than others (~9%). It is also observed that catchment like Chhota Shigri having a combined network of channelized and distributed drainage patterns with lower specific discharge, more glacierized area, low pH, high pCO<sub>2</sub>, Low molar ratio [Ca<sup>2+</sup> + Mg<sup>2+</sup>]/[ Na<sup>+</sup> + K<sup>+</sup>], high SMF (~ 0.4), low CO<sub>2 carbonate</sub>/CO<sub>2 silicate</sub> ratio (~1.3) show relatively more sulphide oxidative and silicate weathered products than other catchments. Conversely, presence of excess non-glaciated areas in Stok and Phutse having well-channelized subsurface discharge with high CO<sub>2 carbonate</sub>/CO<sub>2 silicate </sub>ratio (~10 to ~5) show enhanced carbonation via atmospheric CO<sub>2</sub> (CAC) and carbonate dissolution with high annual CO<sub>2</sub> sequestration. Thus, varying subglacial drainage system, specific discharge pattern and reactive rock-types with distinct hydro-micro-climatic set up alters the chemical weathering mechanism in these catchments and control meltwater quality.</p>