Query that drops all indexes in the given table. Note: unique keys are not affected by this operation.

index_dropper.sql

DO
$do$
DECLARE
   _sql text;
BEGIN
   SELECT 'DROP INDEX ' || string_agg(indexrelid::regclass::text, ', ')
   FROM   pg_index  i
   LEFT   JOIN pg_depend d ON d.objid = i.indexrelid
                          AND d.deptype = 'i'
   WHERE  i.indrelid = 'TABLE_NAME'::regclass  -- Replace the TABLE_NAME with your table's name 
   AND    d.objid IS NULL
   INTO   _sql;
   IF _sql IS NOT NULL THEN
     EXECUTE _sql;
   END IF;
END
$do$;