Necessity means immediate danger of death, or in extraordinary circumstances, such is in mission fields, when lay catechists have been given the faculty to baptize. If your bishop has not personally instructed you and given you that faculty, to exercise with specific individuals in specific circumstances, you have not the authority to baptize licitly.
This is not congruent to canon law.
CHAPTER II.
THE MINISTER OF BAPTISM
Can. 861 §1. The ordinary minister of baptism is a bishop, a presbyter, or a deacon, without prejudice to the prescript of ⇒ can. 530, n. 1.
§2. When an ordinary minister is absent or impeded, a catechist or another person designated for this function by the local ordinary, or in a case of necessity any person with the right intention, confers baptism licitly. Pastors of souls, especially the pastor of a parish, are to be concerned that the Christian faithful are taught the correct way to baptize.
Can. 862 Except in a case of necessity, no one is permitted to confer baptism in the territory of another without the required permission, not even upon his own subjects.
Can. 863 The baptism of adults, at least of those who have completed their fourteenth year, is to be deferred to the diocesan bishop so that he himself administers it if he has judged it Expedient.
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Can. 865 §1. For an adult to be baptized, the person must have manifested the intention to receive baptism, have been instructed sufficiently about the truths of the faith and Christian obligations, and have been tested in the Christian life through the catechumenate. The adult is also to be urged to have sorrow for personal sins.
§2. An adult in danger of death can be baptized if, having some knowledge of the principal truths of the faith, the person has manifested in any way at all the intention to receive baptism and promises to observe the commandments of the Christian religion.
Can. 866 Unless there is a grave reason to the contrary, an adult who is baptized is to be confirmed immediately after baptism and is to participate in the eucharistic celebration also by receiving communion
Can. 867 §1. Parents are obliged to take care that infants are baptized in the first few weeks; as soon as possible after the birth or even before it, they are to go to the pastor to request the sacrament for their child and to be prepared properly for it.
§2. An infant in danger of death is to be baptized without delay.
Can. 868 §1. For an infant to be baptized licitly:
1/ the parents or at least one of them or the person who legitimately takes their place must consent;
2/ there must be a founded hope that the infant will be brought up in the Catholic religion; if such hope is altogether lacking, the baptism is to be delayed according to the prescripts of particular law after the parents have been advised about the reason.
§2. An infant of Catholic parents or even of non-Catholic parents is baptized licitly in danger of death even against the will of the parents.
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Can. 871 If aborted fetuses are alive, they are to be baptized insofar as possible.
ibid.
Immanent danger of death requires no permissions, save the law itself. (Can. 868 §2, 865 §2)
A aborted or miscarried child does not, either; again, by the law itself the layman has the licity and faculty. (Can. 871)
An infant is to be baptized within a few weeks (Can 867 §1); essentially, if not able to be baptized within the month, they should be baptized by a catechist with approval, but should none be available, a layman may baptize them licitly, since being unable to obey another canon constitutes necessity. Necessity itself grants the faculty to baptize (Can 861, 862)