No 12539, Saturday 02 Feb 2019, Afterdark

Across

1. Arraignment in a civil court at America to detain a nationalist (10) ACCUSATION {A}{CC}{USA}{T{I}O}{N}
6. Longing to be in ground without pressure (4) ITCH {pITCH}
10. Villagers conduct rituals in upper house (9) RURALISTS {R{RITUALS*}S}
11. He came back to fix painting in the place where we live (5) EARTH {E{ART}H<=}
12. Street musicians featuring on paper collect grub, half of it with diners card (5-8) ORGAN GRINDERS {ORGAN}{GRub}{DINERS*}
14. Drink with man by the side (4) TEAM {TEA}{M}
15. One in ten die at the borders, death being accidental (10) UNINTENDED {UN}{IN}TEN}{DiE}{D}
17. Tension is not changeable (3,2,5) SET IN STONE Anno not clear (Addendum - {TENSION}* [RA] See comments)
21. Contents of drug, lithium found in fruit (4) UGLI (T)
23. Democrat is a villain, almost picks on others regularly and isolates (13) DISCRIMINATES {D}{IS}{CRIMINal}{oThErS}
25. Fabric made by nitwit, essentially bad (5) TWILL {niTWit}{ILL}
26. A male friend and girl with love, over the moon in involvement (9) IMBROGLIO {I}{M}{BRO}{G}{L}{IO}
27. Scoundrel, he's frequently found in cell (4) HEEL {HE}{cElL}
28. Malignant mass, test shows independent secondary growth (10) METASTASIS {MASS+TEST*}{I}{S}

Down

1. Perhaps an attendant to assist hero in transportation (3,7) AIR HOSTESS {ASSIST+HERO*}
2. Actor gets vote for award right away (4,5) CARY GRANT {CARrY}{GRANT}
3. Quiet and fast, primarily seen inching ahead (6) SILENT {Seen}{Inching}{LENT}
4. Rehearsal turns ugly after the leading hero is ousted (4,3) TEST RUN {ThE}{TURNS*}
5. Antibody for poison, new invention finally (7) OPSONIN {POISON*}{inventioN}
7. Standing of communism retractable? Somewhat retrograde... (5) TERMS {T<=}
8. ...to begin with, honestly a horrid antic to laugh (2-2) HA-HA (Acrostic)
9. No power in Erode – Strike (6) DELETE {DEpLETE}
13. Revelations by a top doctor; girl is in distress (10) ADMISSIONS Anno not clear
16. Probe an idol, expose guy having drug (9) DIGITALIS {DIG}{I}{TALISman}
18. Let's get fresh in a corner and cuddle up (6) NESTLE {N{LETS*}E}
19. A machine to regulate? Central bank is involved in it (7) TURBINE {TU{RBI}NE}
20. State non-aligned movement's reason to extradite criminal to American capital (7) NAMIBIA {NAM}{alIBI}{America}
22. Private doctor after getting a name gets boastful basically (6) INMOST {I}{N}{MO}{boaSTful}
23. Tax is an endless nonsense (5) DRIVE {DRIVEl}
24. Fellow is heading out to collect stamp (4) ETCH {fETCH}

Reference List

Civil court=CC, America=USA, A=I, Pressure=P, Upper house=RS, Man=M, One=Un, Democrat=D, Male=M, Girl=G, Love=L, Moon=Io, Indepndent=I, Secondary=S
Right=R, Power=P, An=I, Corner=NE, Central Bank=RBI, Non-aligned Movement=NAM, Criminal=Al, Doctor=Mo, Fellow=F

Colour/Font Scheme

Definition, Solution, Component letters, Embedded links, Theme word,  Anagram Indicator, C/C indicator, Reversal Indicator, Hidden word Indicator, Letter Pick indicator, Deletion Indicator, Homophone Indicator, Movement Indicator, Positional Indicator, Substitution, Indicator, Link/Connector, Extraneous

GRID