Under Pressure
by Kegler

As indicated by 22 Across, COMPRESSED AIR, six synonyms for “air” are “compressed” into single squares.
Represented by red numbers in the grid, the six are: 1=LILT, 2=HYMN, 3=NOEL, 4=ARIA, 5=TUNE, 6=SONG.

Under Pressure grid

Across
1AORTAS (A ROAST anag)
5MOT(I'VE)S (MOST anag)
11TR + ELLIS
12F(URN)ISH
13L(ACER)ATE (CARE anag)
16M(ON)ARCH + Y
18PAIR UP (rev hidden)
21NOOS + E (SOON rev)
22COMPRESSED AIR
23COrAL
27ONTARIO (hidden)
29A + DO + RERS (ERRS anag)
31S(TUC + CO)ING (CUT rev)
32D(A + N + C)ING
33MET(I)ER
34S(T)RETTO (rev)
35PR(O + SOD)Y
Down
1A + TOM
2O(R)LOP (POOL anag)
3REANIMATE (MANEATER I)
4fALTERS
6OUTPOST (TO SPOUT anag)
7TREAT (TATER anag)
8INFIELDER (RILED FINE anag)
9ESAU ("'E SAW" hom)
10SH + APERS
14AMNESIAC (CINEMA AS anag)
15B(ROAD)ENING
17APPL(IAN + C)E
19A/C + CORDS
20DEP(ONE + N)T
24V + I + SIT
25COOlER
26pURGED
28NEAT (2 defs)
30SP(R)Y

Solution