1805, Pollock was again in the mortar-battery, and did good work. After four assaults were repulsed, the siege was converted into a blockade; but on 2 April, when Lake completely defeated Holkar in the field, the rajah of Bharatpúr, dreading the renewal of the siege, hastened to conclude peace. Pollock was promoted captain-lieutenant on 17 Sept. 1805.
Lake moved to Jallor on the Chambal, and Pollock went with his battery to Marabád. In August Lake gave Pollock the command of the artillery of a field force, under Colonel Ball, ordered for the pursuit of Holkar. By December, Holkar, a helpless fugitive, sued for peace, and Pollock was stationed with his battery at Mírat, until he was appointed quartermaster to a battalion of artillery at Dumdum. Later he was made adjutant and quartermaster of the field artillery at Cawnpore; he remained there until his promotion to captain on 1 March 1812, when he was ordered to Dumdum. He was in command of the artillery at Fathgarh in 1813. Shortly afterwards the offer of his services to serve in Nipál was accepted, and in January 1814 he joined Major-general John Sullivan Wood's division at Jeitpúr, with reinforcements of two companies of artillery. Finding himself senior officer of artillery, he took command of that arm in the division. On the conclusion of hostilities Pollock returned to Dumdum, and in 1815 was given the appointment of brigade-major of the Bengal artillery. For some years he remained in cantonments. He was promoted brevet-major on 12 Aug. 1819, and regimental major on 4 May 1820.
In 1820 he was appointed assistant adjutant-general of artillery, a post which he held until his promotion to a regimental lieutenant-colonelcy on 1 May 1824. In 1824 the first Burmese war began, and Pollock, ordered to the front, arrived at the seat of war after the capture of Rangoon. He did much good work in organising the artillery and completing the equipment. In February 1825 he accompanied the commander-in-chief in his advance on Prome, moving by water up the Irrawaddy, with his detachment of artillery and guns. Prome was entered on 25 April. He took part in the operations near Prome in November and December, commanding the artillery of General Willoughby Cotton's division in the march and capture of Mallown. He was specially mentioned in despatches for the prominent part he had taken in the bombardment of Mallown. On 25 Jan. 1826 the army marched on Ava, and came upon the enemy between Yebbay and Pagahm on 9 Feb. The Burmese were defeated, and Pagahm Mew, with all its stores, ordnance, and ammunition, fell to the British. Pollock took his full share in the day's proceedings, in which the artillery again took the most prominent part. On 16 Feb. the march on Ava was resumed, and the force arrived at Yandabú, some forty-five miles from Ava, on the 22nd. Here the treaty of peace was signed. On 8 March the army left Yandabú. Pollock's services in the campaign were specially acknowledged by the governor-general in council, and he was made a C.B. On his return to Calcutta his health was so much shaken by the hardships of the campaign that he received sick leave to proceed to Europe early in 1827. He was promoted brevet-colonel in the company's service on 1 Dec. 1829.
He returned to India in 1830, and was posted to the command of a battalion of artillery at Cawnpore. He was promoted regimental colonel and colonel-commandant of the Bengal artillery on 3 March 1835. In 1838 he was appointed brigadier-general with a divisional command at Dánápúr. From Dánápúr he was transferred to the command of the Agra district. On 28 June 1838 he was promoted major-general.
In November 1841 the disastrous rising at Kábul took place. It was followed in January by the annihilation of the British army in the Khyber pass [see Brydon, William; Macnaghten, Sir William Hay]. Troops were gradually collected at Pesháwar, and Pollock was selected in January 1842 to command, with political powers, the expedition for the relief of Sale and his troops at Jalálábád. Pollock reached Pesháwar on 5 Feb. For two months he remained there, waiting for reinforcements and organising his column. Much sickness prevailed among the native troops, and nearly two thousand men were in hospital. The native troops were also somewhat demoralised. Urgent as Pollock understood the case of Jalálábád to be, he preferred to face hostile criticism on his delay to risking anything at such a crisis. On 31 March he advanced with his column to Jamarúd. He had reduced his army baggage to a minimum, and was himself content to share a tent with two officers of his staff. He had conciliated his Sikh allies, and inspired his own native troops with some confidence. On 5 April he advanced to the mouth of the pass, where the enemy had made a formidable barrier in the valley, had taken up strong positions, and had erected redoubts on the high ground to the right and left of the pass. Pollock had made all his arrange-