The most common and most likely answer to this crossword clue is the 6 letter word GREENS
I've seen this crossword clue in The Guardian
G
R
E
E
N
S
More clues leading to the result GREENS
- Political party to welcome mostly opposing points
- Healthy food for environmentalists
- Signs people should go for vegetables
- Topless match, with players from one side in shades
- Some party members are vegetables
- Political party on course
- Leaves party
- Environmentalists in meagre ensemble
- Leaves money for sex
- Ecowarriors putting on these
Buddy explains!

The straight part
We know that "shades" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case shades = greens.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GREENS mean?
GREENS noun- The colour of growing foliage, as well as other plant cells containing chlorophyll; the colour between yellow and blue in the visible spectrum; one of the primary additive colour for transmitted light; the colour obtained by subtracting red and blue from white light using cyan and yellow filters.
- (sometimes capitalised) A member of a green party; an environmentalist.
- A putting green, the part of a golf course near the hole.
- (bowls) The surface upon which bowls is played.
- One of the colour balls used in snooker, with a value of 3 points.
- A public patch of land in the middle of a settlement.
- A grassy plain; a piece of ground covered with verdant herbage.
- (chiefly in plural) Fresh leaves or branches of trees or other plants; wreaths.
- Any substance or pigment of a green colour.
- Marijuana.
- Money.
- One of the three color charges for quarks.
- Leaves and leaf-like parts of edible plants when eaten as vegetables or in salads.
- Green vegetables; edible plants or plant parts that contain chlorophyll.
- Leafy plants that are used for decoration.
- The green uniform of the United States Marine Corps.
- To make (something) green, to turn (something) green.
- To become or grow green in colour.
- To add greenspaces to (a town, etc.).
- To become environmentally aware.
- To make (something) environmentally friendly.