[Gurnanda]

You can find more about Hydrolyzed Rhodophyceae Extract in: https://www.seppic.com/how-can-you-purify-and-protect-your-skin-against-microparticles. Again, this raw material suits if you concept your product image to deal with skin damage caused by pollution.

If you find some material to have direct defense against pollution particle. You might use some chelating agent or film former or adsorbent that effectively bind any dust, impurities and heavy metal (the toughest to deal with). @@Dtdang I live in Malaysia.

[Gurnanda]

FDA in my country regulates that if any product claime anti-pollution then they have to prove that they wash away any dust, impurities and heavy metal (either rinse off or leave on).
This claim could be substantiated by adding some chelating agent or film former or adsorbent that effectively bind any metal. (Dust and common air impurities could be easily washed away by surfactant)

The other alternative is the claim that concepting the image to deal with skin damage caused by pollution. Its visible skin damage could be:
1. Dull oily skin (formulation approach is deep cleansing/exfoliation by scrub)
2. Dry damage skin (formulatiin approach is restore natural lipid layer by ceramides or some natural extract)
3. Dehydrated rough skin (improving skin hydration)
4. Wrinkles (control formation of ROS by antioxidant agent)
5. Uneven skin tone (add lightening agent)
6. Loss of skin firmness (promoting collagen synthesis)
7. Skin redness/acnes (ads inflamamatory active agents)

this is my experience based on market condition in my region (APAC). do you have any other insight for this? ?

[Gurnanda]

Have you use hyalurinic acid? When added to cosmetic formulations, Sodium Hyaluronate helps to increase the final product’s stability and to reduce the probability of oxidization. Cleansers and moisturizers that are enriched with this hydrating agent will not leave the skin with an oily residue. 
Due to its inclination to form clumps when its introduce to water, SH can first be blend with Glycerine befire being added to water. This will prevent clumping and encourage a smooth blend. Or alternatively it could simply add directly to water, covered, give it time to hydrate and after which it can be mixed well. If you work with a largel volume, it could add directly to water using stick immersion blender, stir it until the consistency thicken.