How much pollution would it take to stop global warming?
I found a decent review article by Zhang et al. (2015) covering various geo-engineering proposals that is worth reading. As for atmospheric pollution, they report that pollution should be injected at controlled altitudes into the stratosphere, where it is longer-lived. Using $\text{SO}_2$, apparently around $2-7 \text{Tg}$ of stratospheric injection would be needed, which is substantially lower than the global $\text{SO}_2$ emissions (e.g. Lee et al. (2011) report annual emissions around $50\text{Tg}$ $\text{S}$, probably the figure has decreased a bit since then).
So, as for your question, it is not about simply polluting more but about controlledly injecting pollutants into the correct atmospheric layers.
References
Lee et al., SO2 emissions and lifetimes: Estimates from inverse modeling using in situ and global, space‐based (SCIAMACHY and OMI) observations, Journal of Geophysical Research Atmospheres 116 (2011), https://doi.org/10.1029/2010JD014758
Zhang et al., Review of geoengineering approaches to mitigating climate change, Journal of Cleaner Production 103 (2015), pp. 898-907, https://doi.org/10.1016/j.jclepro.2014.09.076, available at http://www.homepages.ed.ac.uk/shs/Climatechange/Geo-politics/Comparisons.pdf