The simple answer from various judicial pronouncement is in negative i.e summon can not be issued without pending proceeding under Income Tax Act. However, the provision u/s 131 of the Income Tax Act itself, nowhere mentions such limitation. This is unlike section 133(6) of the Income Tax Act which clearly mentions that if there is no pending proceeding, the Assessing Officer can seek the information after obtaining permission from the Commissioner of Income Tax. But , similar limitations are not provided under section 131.
As the provision u/s 131 of the I.T. Act itself does not provide anywhere that A.O cannot issue notice u/s 131 without any proceeding, the legislature intention was examined by High Court and was held in a number of rulings that power u/s 131(1) can not be used without a pending proceeding. A distinction was made between section 131(1) and section 131(1A) of the I .T Act. Under bother the provision, the power remains same, however, under section 131(1A) , it is additionally mentioned that notwithstanding that no proceedings with respect to such person or class of persons are pending before him or any other income-tax authority. Thus, from language itself, it was interpreted that while for invoking section 131(1), there must be pending proceeding before Assessing Officer, no such requirement is there for invoking power by investigation wing u/s 131(1A) of the I.T.Act.
Case laws on power of Summon u/s 131 :
1. The Bombay High Court in Jamnadas Madhavji and Co. v. J. B. Panchal, ITO  162 I TR 331 held that (pages 336 and 337)
The Taxation Laws (Amendment) Act, 1975, introduced sub-section (1A) in section 131. Under this sub-section, if the Assistant Director of Inspection has reason to suspect that any income has been concealed…then, for any enquiry or investigation relating thereto, it shall be competent for him to exercise the powers conferred under sub-section (1) of section 131, ‘notwithstanding that no proceedings with respect to such person or class of persons are pending before him or any other income-tax authority’.
Absence of this non obstante clause in section 131(1) is significant. Reading section 131(1) and section 131 (1A) together, it is obvious that whereas an officer mentioned in sub-section (1) can exercise powers there under only if a proceeding is pending before him, the officer mentioned in section 131 (1A), viz., the Assistant Director of Inspection, can exercise such powers notwithstanding that no proceedings are pending before him or before any other officer …
Also relevant to the context is the form of the summons under section 131(1) which commences with the words: ‘whereas your attendance is required in connection with the proceedings under the Income-tax Act in your case’…. The form also assumes and presupposes the existence of a pending proceeding before the concerned officer. Further, Explanation 2 to section 132 of the Act also indicates that but for its artificial and extended definition of the word ‘proceeding’, proceeding would mean one actually pending and not one completed and concluded.”
2. In Rina Sen v. CIT  235 ITR 219 the Patna High Court held as follows
“The existence of a pending proceeding is a condition precedent and sina qua non for the exercise of power under section 131(1) of the Income-tax Act, 1961. The words ‘notwithstanding that no proceeding with respect to such person or class of persons are pending’ occurring in sub-section (1A) of section 131 leave no room for doubt that while the authorities specified under section 131 (1A) of the Act are empowered to take action if there is ‘reason to suspect’ that any income has been concealed or is likely to be concealed by any person or class of persons even though no proceeding with respect to such person or class of persons is pending before him or any other income-tax authority, the authorities specified in section 131(1) of the Act can do so only if a proceeding is pending before them. The proceeding within the meaning of section 131(1) of the Act must, therefore, be an independent proceeding pending from before and it is only in connection with that proceeding that commission can be issued.”
3. In case of CIT v. Navendram Ahuja  197 CTR (MP) 462..
the commission was issued long prior to the commencement of assessment proceeding relating to assessment year 1990-91 and in that back drop considering the scope and ambit of section 131(1)( d ) of the Act, it was held that—
“. . . Section 131(1)( d ) of the Act provides that the Assessing Officer shall have the same powers as are vested in a [Civil] Court under the CPC, 1908, when trying a suit, in respect of the matters enumerated including issue of commission. What is significant is use of the words ‘when trying a suit’. A Court can issue a commission only during the pendency of the suit. As the powers, vested in the Assessing Officer are same powers as are vested in a Court, it follows that the Assessing Officer can issue a commission only if a proceeding is pending before him. “
This decision was followed in another case Choudahry Builders Private Ltd vs Principal Secretary, Union of India 295 ITR 98 (MP)/