Original query:

select count(distinct(a.audited_obj_id)),ast_area from test_dm_audittrail_s  a where   a.object_type='pac' and a.ast_area is not null and time_stamp between date'2019-01-25 00:00:00' and date'2020-01-25 00:00:00' group by a.ast_area;

Prettified:

SELECT
  count(DISTINCT "a"."audited_obj_id"),
  "ast_area"
FROM
  "test_dm_audittrail_s" a
WHERE
  "a"."object_type" = 'pac' AND
  "a"."ast_area" IS NOT NULL AND
  "time_stamp" BETWEEN '2019-01-25 00:00:00'::date AND '2020-01-25 00:00:00'::date
GROUP BY
  "a"."ast_area"